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

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.

Published: 2025-07-23 Last update: 2025-08-05 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-53537 is rated Moderate Risk (55.2/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.63%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-53537

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-19 0.16% 0.63% +0.47%
2 2026-04-18 0.05% 0.16% +0.11%
3 2025-07-29 — 0.05% —

Full EPSS history (4 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-53537

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2025-53537

OS Trackers for CVE-2025-53537

vendor priority summary link
alpine — CVE-2025-53537: 1 source package rows (libhtp); 5 state rows across 3 repos (3.22-community, 3.23-community, edge-community); fixed 0, open 5. https://security.alpinelinux.org/vuln/CVE-2025-53537
debian unimportant CVE-2025-53537 unimportant priority: Debian including 1 source packages (libhtp), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2025-53537
suse high — https://www.suse.com/security/cve/CVE-2025-53537/
ubuntu medium CVE-2025-53537 medium priority: Ubuntu including 1 source packages (libhtp), 8 status rows across 8 suites (bionic, focal, jammy, noble, plucky, questing, upstream, xenial): released 7, needed 1. https://ubuntu.com/security/CVE-2025-53537

Affected software / configurations for CVE-2025-53537

Vendor Product Version Raw CPE
oisf libhtp < 0.5.51 cpe:2.3:a:oisf:libhtp:*:*:*:*:*:*:*:*

References for CVE-2025-53537

cvelogic Threat Intelligence