cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.27.0, a vulnerability allows attacker-controlled HTTP headers to influence server-visible metadata, logging, and authorization decisions. An attacker can supply X-Forwarded-For or X-Real-IP headers which get accepted unconditionally by get_client_ip() in docker/main.cc, causing access and error logs (nginx_access_logger / nginx_error_logger) to record spoofed client IPs (log poisoning / audit evasion). This vulnerability is fixed in 0.27.0.

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

  - cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.27.0, a
    vulnerability allows attacker-controlled HTTP headers to influence server-visible metadata, logging, and
    authorization decisions. An attacker can supply X-Forwarded-For or X-Real-IP headers which get accepted
    unconditionally by get_client_ip() in docker/main.cc, causing access and error logs (nginx_access_logger /
    nginx_error_logger) to record spoofed client IPs (log poisoning / audit evasion). This vulnerability is
    fixed in 0.27.0. (CVE-2025-66577)

The remote Fedora 42 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-3b0e5b457d advisory.

    # Update to 0.30.1

    - [Denial of service (DOS) using zip bomb (CVE-2026-22776)](https://github.com/yhirose/cpp-     httplib/security/advisories/GHSA-h934-98h4-j43q)
    - [CRLF injection in http headers (CVE-2026-21428)](https://github.com/yhirose/cpp-     httplib/security/advisories/GHSA-wpc6-j37r-jcx7)
    - [Untrusted HTTP Header Handling: X-Forwarded-For/X-Real-IP Trust     (CVE-2025-66577)](https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-gfpf-r66f-5mh2)

    https://github.com/yhirose/cpp-httplib/releases/tag/v0.30.1

Tenable has extracted the preceding description block directly from the Fedora 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 Fedora 43 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-e50e41fcea advisory.

    # Update to 0.30.1

    - [Denial of service (DOS) using zip bomb (CVE-2026-22776)](https://github.com/yhirose/cpp-     httplib/security/advisories/GHSA-h934-98h4-j43q)
    - [CRLF injection in http headers (CVE-2026-21428)](https://github.com/yhirose/cpp-     httplib/security/advisories/GHSA-wpc6-j37r-jcx7)
    - [Untrusted HTTP Header Handling: X-Forwarded-For/X-Real-IP Trust     (CVE-2025-66577)](https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-gfpf-r66f-5mh2)

    https://github.com/yhirose/cpp-httplib/releases/tag/v0.30.1


Tenable has extracted the preceding description block directly from the Fedora 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 openSUSE 16 host has packages installed that are affected by multiple vulnerabilities as referenced in the openSUSE-SU-2026:20056-1 advisory.

    - CVE-2025-66570: IP spoofing, log poisoning, and authorization bypass via header shadowing due to     acceptance and       parsing of client-controlled injected HTTP headers in incoming requests (bsc#1254734).
    - CVE-2025-66577: access and error log poisoning with spoofed client IPs due to unconditional acceptance     of       client-controlled `X-Forwarded-For` and `X-Real-IP` headers (bsc#1254735).

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.

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

  - cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.27.0, a     vulnerability allows attacker-controlled HTTP headers to influence server-visible metadata, logging, and     authorization decisions. An attacker can supply X-Forwarded-For or X-Real-IP headers which get accepted     unconditionally by get_client_ip() in docker/main.cc, causing access and error logs (nginx_access_logger /     nginx_error_logger) to record spoofed client IPs (log poisoning / audit evasion). This vulnerability is     fixed in 0.27.0. (CVE-2025-66577)

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

ID	Name	Product	Family	Type	Severity
463440	Echo: cpp-httplib: security update to 0.18.7-1+e2	Tenable Cloud Security	Echo Local Security Checks	Local	medium
463440	Echo: cpp-httplib: security update to 0.18.7-1+e2	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	medium
294951	Fedora 42 : cpp-httplib (2026-3b0e5b457d)	Nessus	Fedora Local Security Checks	Local	high
294942	Fedora 43 : cpp-httplib (2026-e50e41fcea)	Nessus	Fedora Local Security Checks	Local	high
291337	openSUSE 16 Security Update : cpp-httplib (openSUSE-SU-2026:20056-1)	Nessus	SuSE Local Security Checks	Local	critical
277711	Linux Distros Unpatched Vulnerability : CVE-2025-66577	Nessus	Misc.	Local	medium

Detections

Analytics

CVE-2025-66577

medium

Tenable Plugins

medium

medium

high

high

critical

medium