CVE-2026-86143: CWE-192 Integer Coercion Error in xmlsoft libxml2
Description
CVE-2026-86143 is an integer coercion error in libxml2 before version 2.15.4. The vulnerability arises from an inconsistency between xmlOutputWriteCallback and xmlBufUse, allowing negative lengths to be passed to write callbacks due to a missing integer overflow check. This flaw can impact confidentiality, integrity, and availability in affected systems.
CVSS v3.1
Score 6.9medium
Affected software
xmlsoft
libxml2
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
In libxml2 versions prior to 2.15.4, the xmlIO component contains a vulnerability where an inconsistency between xmlOutputWriteCallback and xmlBufUse functions permits negative length values to reach write callbacks. This occurs because there is no check for integer overflow before invoking the write callback, leading to potential misuse of the length parameter within the callback. The issue is classified as CWE-192 (Integer Coercion Error) and has security relevance for various uses of the length value in callbacks.
Potential Impact
The vulnerability can lead to high confidentiality and integrity impacts, and a low impact on availability, as indicated by the CVSS vector. This suggests that exploitation could allow unauthorized data disclosure or modification. However, the attack complexity is high, and no privileges or user interaction are required. There are no known exploits in the wild at this time.
Mitigation Recommendations
A fix is available in libxml2 version 2.15.4 and later. Users should upgrade to version 2.15.4 or newer to remediate this vulnerability. Patch status is confirmed by the versioning information. No additional mitigation steps are indicated.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mitre
- Date Reserved
- 2026-09-05T04:31:20.849Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a9b9ca2acd9273b4950701b
Added to database: 09/05/2026, 04:37:54 UTC
Last enriched: 09/15/2026, 00:50:18 UTC
Last updated: 10/20/2026, 18:48:24 UTC
Views: 84
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