CVE-2026-76956: CWE-394 Unexpected Status Code or Return Value in libexpat project libexpat
Description
CVE-2026-76956 is a vulnerability in libexpat versions 2.8.2 and 2.8.3 prior to 2.8.4 where the return code of the getentropy function is misinterpreted. This leads to insufficient entropy being used, making the software vulnerable to hash flooding attacks that can cause denial of service through crafted XML content.
CVSS v3.1
Score 5.9medium
Affected software
libexpat project
libexpat
pkg:github/libexpat/libexpatRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
In libexpat versions 2.8.2 and 2.8.3 before 2.8.4, a misinterpretation of the return code from the getentropy function results in insufficient entropy generation. This weakness allows attackers to exploit hash flooding attacks, which can cause denial of service by overwhelming the system with crafted XML input. The vulnerability is tracked as CVE-2026-76956 and is categorized under CWE-394 (Unexpected Status Code or Return Value).
Potential Impact
The vulnerability can be exploited to cause denial of service (DoS) by leveraging insufficient entropy in hash functions, leading to hash flooding attacks. There is no impact on confidentiality or integrity reported. The CVSS v3.1 score is 5.9 (medium severity), indicating a network attack vector with high attack complexity and no privileges or user interaction required.
Mitigation Recommendations
A fix is available in libexpat version 2.8.4. Users should upgrade to version 2.8.4 or later to remediate this vulnerability. Since no vendor advisory or patch links are provided, verify the fix availability from official libexpat project sources before upgrading.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mitre
- Date Reserved
- 2026-08-20T04:22:50.503Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a86e0f3acd9273b4983850c
Added to database: 08/20/2026, 11:11:47 UTC
Last enriched: 09/11/2026, 05:18:18 UTC
Last updated: 10/04/2026, 18:55:08 UTC
Views: 60
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