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OpenAdvisories
Medium · 5.3 CVE-2025-66577 EUVD-2025-201454

cpp-httplib Untrusted HTTP Header Handling: X-Forwarded-For/X-Real-IP Trust

Published Dec 5, 2025 · Updated Dec 5, 2025 · Assigned by GitHub_M

Description

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.

Affected products

VendorProductAffectedFixed
yhirose cpp-httplib < 0.27.0 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 cpp-httplib 0.41.0+ds-3 —
Debian 13 cpp-httplib No fix yet —
Debian 12 cpp-httplib No fix yet —
ReleasePackageFixed inAdvisory
Ubuntu 26.10 cpp-httplib No fix yet —
Ubuntu 25.10 cpp-httplib 0.18.7-1ubuntu0.25.10.1 —
Show 3 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu Pro 26.04 LTS cpp-httplib No fix yet —
Ubuntu Pro 24.04 LTS cpp-httplib 0.14.3+ds-1.1ubuntu0.1~esm1 —
Ubuntu Pro 22.04 LTS cpp-httplib 0.10.3+ds-1ubuntu0.1~esm1 —
ReleasePackageFixed inAdvisory
SLES for SAP 16.0 cpp-httplib 0.22.0-160000.3.1 SUSE-SU-2026:20090-1
SLES 16.0 cpp-httplib 0.22.0-160000.3.1 SUSE-SU-2026:20090-1
ReleasePackageFixed inAdvisory
openSUSE Tumbleweed cpp-httplib 0.28.0-1.1 openSUSE-SU-2025:15844-1
openSUSE Leap 16.0 cpp-httplib 0.22.0-160000.3.1 openSUSE-SU-2026:20056-1

Advisories 3

References