CVE-2025-53537: LibHTP's memory leak with lzma can lead to resource starvation

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-07-23 · updated 2026-06-17
Weakness: CWE-401

Description

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.

Affected products

OISF libhtp: before 0.5.51 — fixed in 0.5.51

How to fix

Upgrade to a fixed version: OISF libhtp 0.5.51. Check the vendor advisory for mitigations.

References

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