TI-2025-33481 Aliases CVE-2025-53537

LibHTP's memory leak with lzma can lead to resource starvation

LOW 39CWE-401Published 2025-07-23 · Updated 2025-07-23

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-401.

Summary

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 it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00502 43rd percentileScored 2026-11-07

Fix Fixed libhtp (OISF): 0.5.51

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
OISF	libhtp	before 0.5.51	0.5.51	Patch available	CNA

libhtp VendorOISF Affected before 0.5.51 Fixed in 0.5.51 Patch available CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:oisf:libhtp::::::::	before 0.5.51	Vulnerable	OISF

cpe:2.3:a:oisf:libhtp:*:*:*:*:*:*:*:* Versions before 0.5.51 Vulnerable ·OISF

Remediation

Fix · CNA libhtp (OISF) Fixed in 0.5.51

Timeline

2026-10-02 Threatist record created from CVE-2025-53537

References

Patch 1

https://github.com/OISF/libhtp/commit/9037ea35110a0d97be5cedf8d31fb4cd9a38c7a7

Advisory 1

https://github.com/OISF/libhtp/security/advisories/GHSA-v3qq-h8mh-vph7

TI-2018-07267 htp_parse_authorization_digest in htp_parsers.c in LibHTP 0.5.26 allows remote attackers… CVSS 3.0CRITICAL 9.8
TI-2024-15831 LibHTP unbounded folded header handling leads to denial service CVSS 3.1HIGH 7.5
TI-2024-30764 LibHTP's unbounded header handling leads to denial service CVSS 3.1HIGH 7.5
TI-2024-19070 Excessive CPU used on malformed traffic CVSS 3.1HIGH 7.5
TI-2015-00864 libhtp 0.5.15 allows remote attackers to cause a denial of service (NULL pointer dereference). CVSS 3.1HIGH 7.5
TI-2019-13009 In OISF LibHTP before 0.5.31, as used in Suricata 4.1.4 and other products, an HTTP… CVSS 3.1MEDIUM 5.3

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences