CVE-2025-53537Network attack vector

Process memory starvation via unreleased LZMA state

Published Jul 23, 2025 · Updated Jul 23, 2025

Memory leak in LibHTP 0.5.50 and earlier allows remote attackers to starve a parsing process of memory through crafted HTTP traffic. The LZMA error path in htp_decompressors.c marks compression complete without freeing the initialized decoder state. Exploitation requires LZMA decompression to remain enabled; repeated triggering exhausts process memory and removes HTTP inspection visibility.

CVSS severity7.5
High
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory leak in LibHTP 0.5.50 and earlier allows remote attackers to starve a parsing process of memory through crafted HTTP traffic. The LZMA error path in htp_decompressors.c marks compression complete without freeing the initialized decoder state. Exploitation requires LZMA decompression to remain enabled; repeated triggering exhausts process memory and removes HTTP inspection visibility.

The record

CVE
CVE-2025-53537
Published
Jul 23, 2025
Updated
Jul 23, 2025
Vendor
Open Information Security Foundation
Product
LibHTP
Classifications
CWE-401, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 23, 2025CVE publishedPublication date reported by the CVE source.
  2. Jul 23, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.5.51

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Open Information Security Foundation · LibHTPversion=< 0.5.51

Published CVSS scores

7.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-401Missing Release of Memory after Effective Lifetime
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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