# CVE-2025-66577: cpp-httplib: cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library

CVE-2025-66577 is fixed in 4 products on 1 platform, first by libcpp-httplib0 0.10.3+ds-1ubuntu0.1~esm1, released December 5, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2025-66577
- Priority: Routine
- CVSS: 5.3 (medium)
- EPSS: 0.0029
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Dec 5, 2025

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | cpp-httplib Debian 14 | 0.41.0+ds-3 | [DEBIAN-CVE-2025-66577](https://patchblox.com/security/data/fix/linux/debian-cve-2025-66577.md) | Dec 5, 2025 |
| Linux | cpp-httplib opensuse-leap 16.0 | 0.22.0-160000.3.1 | [OPENSUSE-SU-2026:20056-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-20056-1.md) | Jan 15, 2026 |
| Linux | cpp-httplib sles 16.0 | 0.22.0-160000.3.1 | [SUSE-SU-2026:20090-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-20090-1.md) | Jan 15, 2026 |
| Linux | libcpp-httplib0 Ubuntu 22.04.1 LTS (jammy) | 0.10.3+ds-1ubuntu0.1~esm1 | [libcpp-httplib0 0.10.3+ds-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libcpp-httplib0-0.10.3-ds-1ubuntu0.1-esm1.md) | Dec 5, 2025 |
| Linux | libcpp-httplib0.14t64 Ubuntu 24.04.5 LTS (noble) | 0.14.3+ds-1.1ubuntu0.1~esm1 | [libcpp-httplib0.14t64 0.14.3+ds-1.1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libcpp-httplib0.14t64-0.14.3-ds-1.1ubuntu0.1-esm1.md) | Dec 5, 2025 |
| Linux | libcpp-httplib0.18 Ubuntu 25.10 (questing) | 0.18.7-1ubuntu0.25.10.1 | [libcpp-httplib0.18 0.18.7-1ubuntu0.25.10.1](https://patchblox.com/security/data/fix/linux/ubuntu-questing-libcpp-httplib0.18-0.18.7-1ubuntu0.25.10.1.md) | Dec 5, 2025 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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