CVE-2025-53537: LibHTP is a security-aware parser for the HTTP protocol and its related bits and pieces

Q: How do I fix CVE-2025-53537?

libhtp: upgrade to 0.5.51. Exact commands for each OS are on this page.

Q: Is CVE-2025-53537 being exploited?

CVE-2025-53537 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2025-53537 affect?

CVE-2025-53537 affects libhtp. Severity is high (CVSS 7.5). LibHTP is a security-aware parser for the HTTP protocol and its related bits and pieces. In versions 0.5.50 and below, there is a traffic-induced memory leak that can starve the process of memory, leading to loss of visibility. To workaroun

Q: How urgent is CVE-2025-53537?

Priority 42/100. High severity; Remotely exploitable, no login, no user action

This month

HIGH 7.5REMOTEUPGRADE

CVE-2025-53537 is a high-severity flaw (CVSS 7.5) affecting libhtp. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 57%)
CISA exploited list	No
Weakness	CWE-401
Published	2025-07-23
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: oisf

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-07-23 21:15 UTCPublished CVE record published
2026-06-17 09:38 UTCUpdated Record last modified

oisf libhtp UPGRADE

Affected: < 0.5.51

Fixed in: 0.5.51

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy libhtp || rpm -q libhtp || libhtp --version

2. UPGRADE to 0.5.51 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade libhtp

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade libhtp

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-53537?

libhtp: upgrade to 0.5.51. Exact commands for each OS are on this page.

Is CVE-2025-53537 being exploited?

CVE-2025-53537 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-53537 affect?

CVE-2025-53537 affects libhtp. Severity is high (CVSS 7.5). LibHTP is a security-aware parser for the HTTP protocol and its related bits and pieces. In versions 0.5.50 and below, there is a traffic-induced memory leak that can starve the process of memory, leading to loss of visibility. To workaroun

How urgent is CVE-2025-53537?

Priority 42/100. High severity; Remotely exploitable, no login, no user action

Software pages

Suricata and Snort vulnerabilities

Related CVEs

CVE-2024-45797 HIGH 7.5 UPGRADE LibHTP is a security-aware parser for the HTTP protocol and the related bits and pieces

References

← Back to latest CVEs