A flaw was found in libsoup, an HTTP client/server library. This HTTP Request Smuggling vulnerability arises from non-RFC-compliant parsing in the soup_filter_input_stream_read_line() logic, where libsoup accepts malformed chunk headers, such as lone line feed (LF) characters instead of the required carriage return and line feed (CRLF). A remote attacker can exploit this without authentication or user interaction by sending specially crafted chunked requests. This allows libsoup to parse and process multiple HTTP requests from a single network message, potentially leading to information disclosure.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - A flaw was found in libsoup, an HTTP client/server library. This HTTP Request Smuggling vulnerability
    arises from non-RFC-compliant parsing in the soup_filter_input_stream_read_line() logic, where libsoup
    accepts malformed chunk headers, such as lone line feed (LF) characters instead of the required carriage
    return and line feed (CRLF). A remote attacker can exploit this without authentication or user interaction
    by sending specially crafted chunked requests. This allows libsoup to parse and process multiple HTTP
    requests from a single network message, potentially leading to information disclosure. (CVE-2026-1801)

The AlmaLinux 9.2 host has packages installed that are affected by multiple vulnerabilities as referenced in the TuxCare ALMALINUX9.2:CLSA-2026:1776854729 advisory.

  - A flaw was found in libsoup, an HTTP client/server library. This HTTP Request Smuggling vulnerability     arises from non-RFC-compliant parsing in the soup_filter_input_stream_read_line() logic, where libsoup     accepts malformed chunk headers, such as lone line feed (LF) characters instead of the required carriage     return and line feed (CRLF). A remote attacker can exploit this without authentication or user interaction     by sending specially crafted chunked requests. This allows libsoup to parse and process multiple HTTP     requests from a single network message, potentially leading to information disclosure. (CVE-2026-1801)

  - A flaw was identified in libsoup, a widely used HTTP library in GNOME-based systems. When processing     specially crafted HTTP Range headers, the library may improperly validate requested byte ranges. In     certain build configurations, this could allow a remote attacker to access portions of server memory     beyond the intended response. Exploitation requires a vulnerable configuration and access to a server     using the embedded SoupServer component. (CVE-2026-2443)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The AlmaLinux 9.6 host has packages installed that are affected by multiple vulnerabilities as referenced in the TuxCare ALMALINUX9.6:CLSA-2026:1776855452 advisory.

  - A flaw was found in libsoup, an HTTP client/server library. This HTTP Request Smuggling vulnerability     arises from non-RFC-compliant parsing in the soup_filter_input_stream_read_line() logic, where libsoup     accepts malformed chunk headers, such as lone line feed (LF) characters instead of the required carriage     return and line feed (CRLF). A remote attacker can exploit this without authentication or user interaction     by sending specially crafted chunked requests. This allows libsoup to parse and process multiple HTTP     requests from a single network message, potentially leading to information disclosure. (CVE-2026-1801)

  - A flaw was identified in libsoup, a widely used HTTP library in GNOME-based systems. When processing     specially crafted HTTP Range headers, the library may improperly validate requested byte ranges. In     certain build configurations, this could allow a remote attacker to access portions of server memory     beyond the intended response. Exploitation requires a vulnerable configuration and access to a server     using the embedded SoupServer component. (CVE-2026-2443)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Rocky Linux 9.6 host has packages installed that are affected by multiple vulnerabilities as referenced in the TuxCare ALMALINUX9.6:CLSA-2026:1776855452 advisory.

  - A flaw was found in libsoup, an HTTP client/server library. This HTTP Request Smuggling vulnerability     arises from non-RFC-compliant parsing in the soup_filter_input_stream_read_line() logic, where libsoup     accepts malformed chunk headers, such as lone line feed (LF) characters instead of the required carriage     return and line feed (CRLF). A remote attacker can exploit this without authentication or user interaction     by sending specially crafted chunked requests. This allows libsoup to parse and process multiple HTTP     requests from a single network message, potentially leading to information disclosure. (CVE-2026-1801)

  - A flaw was identified in libsoup, a widely used HTTP library in GNOME-based systems. When processing     specially crafted HTTP Range headers, the library may improperly validate requested byte ranges. In     certain build configurations, this could allow a remote attacker to access portions of server memory     beyond the intended response. Exploitation requires a vulnerable configuration and access to a server     using the embedded SoupServer component. (CVE-2026-2443)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS / Pro Realtime 22.04 LTS / Pro Realtime 24.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8780-1 advisory.

    It was discovered that libsoup incorrectly handled certain URLs when using an HTTP proxy. A remote     attacker could possibly use this issue to inject arbitrary HTTP headers. (CVE-2026-1467)

    It was discovered that libsoup did not remove proxy authentication credentials when following HTTP     redirects. A remote attacker could possibly use this issue to obtain sensitive information.
    (CVE-2026-1539)

    Ahmed Lekssays discovered that libsoup incorrectly parsed certain HTTP requests. A remote attacker could     possibly use this issue to obtain sensitive information. (CVE-2026-1801)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote NewStart CGSL host, running version MAIN 7.02, has libsoup packages installed that are affected by multiple vulnerabilities:

  - A flaw was found in libsoup. An integer underflow vulnerability occurs when processing content with a     zero-length resource, leading to a buffer overread. This can allow an attacker to potentially access     sensitive information or cause an application level denial of service. (CVE-2026-2369)

  - GNOME libsoup before 3.6.0 allows HTTP request smuggling in some configurations because '\0' characters at     the end of header names are ignored, i.e., a Transfer-Encoding\0: chunked header is treated the same as     a Transfer-Encoding: chunked header. (CVE-2024-52530)

  - A flaw was found in the cookie date handling logic of the libsoup HTTP library, widely used by GNOME and     other applications for web communication. When processing cookies with specially crafted expiration dates,     the library may perform an out-of-bounds memory read. This flaw could result in unintended disclosure of     memory contents, potentially exposing sensitive information from the process using libsoup.
    (CVE-2025-11021)

  - A flaw in libsoup's HTTP header handling allows multiple Host: headers in a request and returns the last     occurrence for server-side processing. Common front proxies often honor the first Host: header, so this     mismatch can cause vhost confusion where a proxy routes a request to one backend but the backend     interprets it as destined for another host. This discrepancy enables request-smuggling style attacks,     cache poisoning, or bypassing host-based access controls when an attacker supplies duplicate Host headers.
    (CVE-2025-14523)

  - A flaw was found in libsoup. The package is vulnerable to a heap buffer over-read when sniffing content     via the skip_insight_whitespace() function. Libsoup clients may read one byte out-of-bounds in response to     a crafted HTTP response by an HTTP server. (CVE-2025-2784)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLES12 host has packages installed that are affected by a vulnerability as referenced in the SUSE- SU-2026:2702-1 advisory.

    This update for libsoup fixes the following issue

    - CVE-2026-1801: HTTP Request Smuggling in soup_filter_input_stream_read_line() (bsc#1257649).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 host has packages installed that are affected by a vulnerability as referenced in the SUSE-SU-2026:2654-1 advisory.

    This update for libsoup2 fixes the following issue

    - CVE-2026-1801: HTTP Request Smuggling in soup_filter_input_stream_read_line() (bsc#1257649).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:2314-1 advisory.

    This update for libsoup fixes the following issues

    - CVE-2026-1801: HTTP Request Smuggling in soup_filter_input_stream_read_line() (bsc#1257649).
    - CVE-2026-4271: use-after-free in the HTTP/2 server when user signal handlers disconnect connections     during callback       execution (bsc#1259767).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

According to the versions of the libsoup packages installed, the EulerOS installation on the remote host is affected by the following vulnerabilities :

    A flaw was found in libsoup, an HTTP client/server library. This HTTP Request Smuggling vulnerability     arises from non-RFC-compliant parsing in the soup_filter_input_stream_read_line() logic, where libsoup     accepts malformed chunk headers, such as lone line feed (LF) characters instead of the required carriage     return and line feed (CRLF). A remote attacker can exploit this without authentication or user interaction     by sending specially crafted chunked requests. This allows libsoup to parse and process multiple HTTP     requests from a single network message, potentially leading to information disclosure.(CVE-2026-1801)

    A flaw was found in libsoup's WebSocket frame processing when handling incoming messages. If a non-default     configuration is used where the maximum incoming payload size is unset, the library may read memory     outside the intended bounds. This can cause unintended memory exposure or a crash. Applications using     libsoup's WebSocket support with this configuration may be impacted.(CVE-2026-0716)

    A flaw was identified in libsoup, a widely used HTTP library in GNOME-based systems. When processing     specially crafted HTTP Range headers, the library may improperly validate requested byte ranges. In     certain build configurations, this could allow a remote attacker to access portions of server memory     beyond the intended response. Exploitation requires a vulnerable configuration and access to a server     using the embedded SoupServer component.(CVE-2026-2443)

    A flaw was found in libsoup. An integer underflow vulnerability occurs when processing content with a     zero-length resource, leading to a buffer overread. This can allow an attacker to potentially access     sensitive information or cause an application level denial of service.(CVE-2026-2369)

Tenable has extracted the preceding description block directly from the EulerOS libsoup security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-1778 advisory.

    OOB Read via Integer Overflow on libsoup through libsoup/websocket/soup-websocket-connection.c via     process_frame() leads to Undefined Behavior (CVE-2026-0716)

    A flaw was found in libsoup, an HTTP client library. This vulnerability, known as CRLF (Carriage Return     Line Feed) Injection, occurs when an HTTP proxy is configured and the library improperly handles URL-     decoded input used to create the Host header. A remote attacker can exploit this by providing a specially     crafted URL containing CRLF sequences, allowing them to inject additional HTTP headers or complete HTTP     request bodies. This can lead to unintended or unauthorized HTTP requests being forwarded by the proxy,     potentially impacting downstream services. (CVE-2026-1467)

    A flaw was found in SoupServer. This HTTP request smuggling vulnerability occurs because SoupServer     improperly handles requests that combine Transfer-Encoding: chunked and Connection: keep-alive headers. A     remote, unauthenticated client can exploit this by sending specially crafted requests, causing SoupServer     to fail to close the connection as required by RFC 9112. This allows the attacker to smuggle additional     requests over the persistent connection, leading to unintended request processing and potential denial-of-     service (DoS) conditions. (CVE-2026-1760)

    A flaw was found in libsoup. This stack-based buffer overflow vulnerability occurs during the parsing of     multipart HTTP responses due to an incorrect length calculation. A remote attacker can exploit this by     sending a specially crafted multipart HTTP response, which can lead to memory corruption. This issue may     result in application crashes or arbitrary code execution in applications that process untrusted server     responses, and it does not require authentication or user interaction. (CVE-2026-1761)

    A flaw was found in libsoup, an HTTP client/server library. This HTTP Request Smuggling vulnerability     arises from non-RFC-compliant parsing in the soup_filter_input_stream_read_line() logic, where libsoup     accepts malformed chunk headers, such as lone line feed (LF) characters instead of the required carriage     return and line feed (CRLF). A remote attacker can exploit this without authentication or user interaction     by sending specially crafted chunked requests. This allows libsoup to parse and process multiple HTTP     requests from a single network message, potentially leading to information disclosure. (CVE-2026-1801)

    Denial of Service via use-after-free in SoupServer during TLS handshake (CVE-2026-2436)

    libsoup includes an embedded HTTP/1 server. When a server sits behind a proxy / load balancer, it's     critical that every hop agrees on how request bodies are framed.In the affected code path, libsoup     accepted HTTP/1 requests with ambiguous body framing:

    multiple Content-Length headers (CL.CL)

    Transfer-Encoding: chunked together with Content-Length (TE+CL)

    Different intermediaries pick different framing rules in these cases. If a front-end and back-end     disagree, an attacker can desynchronize the connection and smuggle an extra request through the chain.
    Depending on deployment, this can lead to routing/ACL bypass, cache poisoning, or reaching internal-only     endpoints. (CVE-2026-2708)

    A flaw was found in libsoup. When establishing HTTPS tunnels through a configured HTTP proxy, sensitive     session cookies are transmitted in cleartext within the initial HTTP CONNECT request. A network-positioned     attacker or a malicious HTTP proxy can intercept these cookies, leading to potential session hijacking or     user impersonation. (CVE-2026-5119)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-1758 advisory.

    OOB Read via Integer Overflow on libsoup through libsoup/websocket/soup-websocket-connection.c via     process_frame() leads to Undefined Behavior (CVE-2026-0716)

    A flaw was found in libsoup, an HTTP client library. This vulnerability, known as CRLF (Carriage Return     Line Feed) Injection, occurs when an HTTP proxy is configured and the library improperly handles URL-     decoded input used to create the Host header. A remote attacker can exploit this by providing a specially     crafted URL containing CRLF sequences, allowing them to inject additional HTTP headers or complete HTTP     request bodies. This can lead to unintended or unauthorized HTTP requests being forwarded by the proxy,     potentially impacting downstream services. (CVE-2026-1467)

    A flaw was found in SoupServer. This HTTP request smuggling vulnerability occurs because SoupServer     improperly handles requests that combine Transfer-Encoding: chunked and Connection: keep-alive headers. A     remote, unauthenticated client can exploit this by sending specially crafted requests, causing SoupServer     to fail to close the connection as required by RFC 9112. This allows the attacker to smuggle additional     requests over the persistent connection, leading to unintended request processing and potential denial-of-     service (DoS) conditions. (CVE-2026-1760)

    A flaw was found in libsoup. This stack-based buffer overflow vulnerability occurs during the parsing of     multipart HTTP responses due to an incorrect length calculation. A remote attacker can exploit this by     sending a specially crafted multipart HTTP response, which can lead to memory corruption. This issue may     result in application crashes or arbitrary code execution in applications that process untrusted server     responses, and it does not require authentication or user interaction. (CVE-2026-1761)

    A flaw was found in libsoup, an HTTP client/server library. This HTTP Request Smuggling vulnerability     arises from non-RFC-compliant parsing in the soup_filter_input_stream_read_line() logic, where libsoup     accepts malformed chunk headers, such as lone line feed (LF) characters instead of the required carriage     return and line feed (CRLF). A remote attacker can exploit this without authentication or user interaction     by sending specially crafted chunked requests. This allows libsoup to parse and process multiple HTTP     requests from a single network message, potentially leading to information disclosure. (CVE-2026-1801)

    A flaw was found in libsoup. When establishing HTTPS tunnels through a configured HTTP proxy, sensitive     session cookies are transmitted in cleartext within the initial HTTP CONNECT request. A network-positioned     attacker or a malicious HTTP proxy can intercept these cookies, leading to potential session hijacking or     user impersonation. (CVE-2026-5119)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - A flaw was found in libsoup, an HTTP client/server library. This HTTP Request Smuggling vulnerability     arises from non-RFC-compliant parsing in the soup_filter_input_stream_read_line() logic, where libsoup     accepts malformed chunk headers, such as lone line feed (LF) characters instead of the required carriage     return and line feed (CRLF). A remote attacker can exploit this without authentication or user interaction     by sending specially crafted chunked requests. This allows libsoup to parse and process multiple HTTP     requests from a single network message, potentially leading to information disclosure. (CVE-2026-1801)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
455565	Echo: libsoup3: security update to 3.6.5-8	Tenable Cloud Security	Echo Local Security Checks	Local	medium
455565	Echo: libsoup3: security update to 3.6.5-8	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	medium
361629	AlmaLinux 9.2 [TuxCare] Security Update: libsoup / libsoup-devel / libsoup-doc Multiple Vulnerabilities (ALMALINUX9.2:CLSA-2026:1776854729)	Nessus	Alma Linux Local Security Checks	Local	medium
352312	AlmaLinux 9.6 [TuxCare] Security Update: libsoup / libsoup-devel / libsoup-doc Multiple Vulnerabilities (ALMALINUX9.6:CLSA-2026:1776855452)	Nessus	Alma Linux Local Security Checks	Local	medium
352296	Rocky Linux 9.6 [TuxCare] Security Update: libsoup / libsoup-devel / libsoup-doc Multiple Vulnerabilities (ALMALINUX9.6:CLSA-2026:1776855452)	Nessus	Rocky Linux Local Security Checks	Local	medium
348241	Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 24.04 LTS / 26.04 LTS / Pro Realtime 22.04 LTS / Pro Realtime 24.04 LTS : libsoup vulnerabilities (USN-8780-1)	Nessus	Ubuntu Local Security Checks	Local	medium
343555	NewStart CGSL MAIN 7.02 : libsoup Multiple Vulnerabilities (NS-SA-2026-0100)	Nessus	NewStart CGSL Local Security Checks	Local	high
324874	SUSE SLES12: libsoup-2_4-1 / libsoup-2_4-1-32bit / libsoup-devel / libsoup-lang / etc (SUSE-SU-2026:2702-1)	Nessus	SuSE Local Security Checks	Local	medium
323242	SUSE SLED15: libsoup-2_4-1 / libsoup2-devel / libsoup2-lang / etc (SUSE-SU-2026:2654-1)	Nessus	SuSE Local Security Checks	Local	medium
321043	SUSE SLED15 / SLES15 Security Update : libsoup (SUSE-SU-2026:2314-1)	Nessus	SuSE Local Security Checks	Local	medium
319965	EulerOS 2.0 SP11 : libsoup (EulerOS-SA-2026-2213)	Nessus	Huawei Local Security Checks	Local	critical
319941	EulerOS 2.0 SP11 : libsoup (EulerOS-SA-2026-2251)	Nessus	Huawei Local Security Checks	Local	critical
319827	Amazon Linux 2023 : libsoup3, libsoup3-devel (ALAS2023-2026-1778)	Nessus	Amazon Linux Local Security Checks	Local	high
316949	Amazon Linux 2023 : libsoup, libsoup-devel (ALAS2023-2026-1758)	Nessus	Amazon Linux Local Security Checks	Local	high
297750	Linux Distros Unpatched Vulnerability : CVE-2026-1801	Nessus	Misc.	Local	medium

Detections

Analytics

CVE-2026-1801

medium

Tenable Plugins

medium

medium

medium

medium

medium

medium

high

medium

medium

medium

critical

critical

high

high

medium