# CVE-2025-53537: libhtp2: LibHTP is a security-aware parser for the HTTP protocol and its relatedbits and pieces

CVE-2025-53537 is fixed in 2 products on 1 platform, first by libhtp2 1:0.5.26-1ubuntu0.1~esm1, released July 23, 2025. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2025-53537
- Priority: High
- CVSS: 7.5 (Medium)
- EPSS: 0.0050
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 23, 2025

## Description

LibHTP is a security-aware parser for the HTTP protocol and its relatedbits and pieces. In versions 0.5.50 and below, there is a traffic-inducedmemory leak that can starve the process of memory, leading to loss ofvisibility. To workaround this issue, set `suricata.yamlapp-layer.protocols.http.libhtp.default-config.lzma-enabled` to false. Thisissue is fixed in version 0.5.51.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libhtp Debian 13.5 (trixie) | 1:0.5.50-1+deb13u1 | [DEBIAN-CVE-2025-53537](https://patchblox.com/security/data/fix/linux/debian-cve-2025-53537.md) | Jul 23, 2025 |
| Linux | libhtp2 Ubuntu 18.04.6 LTS (bionic) | 1:0.5.26-1ubuntu0.1~esm1 | [libhtp2 1:0.5.26-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libhtp2-1-0.5.26-1ubuntu0.1-esm1.md) | Jul 23, 2025 |
| Linux | libhtp2 Ubuntu 20.04 LTS (focal) | 1:0.5.32-1ubuntu0.1~esm1 | [libhtp2 1:0.5.32-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libhtp2-1-0.5.32-1ubuntu0.1-esm1.md) | Jul 23, 2025 |
| Linux | libhtp2 Ubuntu 22.04.1 LTS (jammy) | 1:0.5.39-1ubuntu0.1~esm1 | [libhtp2 1:0.5.39-1ubuntu0.1~esm1](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libhtp2-1-0.5.39-1ubuntu0.1-esm1.md) | Jul 23, 2025 |
| Linux | libhtp2 Ubuntu 24.04.5 LTS (noble) | 1:0.5.46-1ubuntu2+esm1 | [libhtp2 1:0.5.46-1ubuntu2+esm1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libhtp2-1-0.5.46-1ubuntu2-esm1.md) | Jul 23, 2025 |
| Linux | libhtp2 Ubuntu 25.04 (plucky) | 1:0.5.49-1ubuntu0.1 | [libhtp2 1:0.5.49-1ubuntu0.1](https://patchblox.com/security/data/fix/linux/ubuntu-plucky-libhtp2-1-0.5.49-1ubuntu0.1.md) | Jan 16, 2026 |

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Data as of 2026-11-08T13:06:02Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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