A flaw was found in libsoup's SoupServer. A remote attacker could exploit a use-after-free vulnerability where the `soup_server_disconnect()` function frees connection objects prematurely, even if a TLS handshake is still pending. If the handshake completes after the connection object has been freed, a dangling pointer is accessed, leading to a server crash and a Denial of Service.

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

  - A flaw was found in libsoup's SoupServer. A remote attacker could exploit a use-after-free vulnerability
    where the `soup_server_disconnect()` function frees connection objects prematurely, even if a TLS
    handshake is still pending. If the handshake completes after the connection object has been freed, a
    dangling pointer is accessed, leading to a server crash and a Denial of Service. (CVE-2026-2436)

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.

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's SoupServer. A remote attacker could exploit a use-after-free vulnerability     where the `soup_server_disconnect()` function frees connection objects prematurely, even if a TLS     handshake is still pending. If the handshake completes after the connection object has been freed, a     dangling pointer is accessed, leading to a server crash and a Denial of Service. (CVE-2026-2436)

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

ID	Name	Product	Family	Type	Severity
464782	Echo: libsoup3: security update to 3.6.6-1	Tenable Cloud Security	Echo Local Security Checks	Local	high
464782	Echo: libsoup3: security update to 3.6.6-1	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	high
319827	Amazon Linux 2023 : libsoup3, libsoup3-devel (ALAS2023-2026-1778)	Nessus	Amazon Linux Local Security Checks	Local	high
301794	Linux Distros Unpatched Vulnerability : CVE-2026-2436	Nessus	Misc.	Local	high

Detections

Analytics

CVE-2026-2436

high

Tenable Plugins

high

high

high

high