CVE-2026-41080
Libexpat Project Libexpat ≤ 2.8.0
Raw vector
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:LCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-41080 is a low-severity Insufficient Entropy (CWE-331) vulnerability in Libexpat Project Libexpat. Its CVSS base score is 2.9 (Low).
Operationally, exploitation aligns with the MITRE ATT&CK technique Brute Force (T1110); ranked at the 33th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SC-12 (Cryptographic Key Establishment and Management) and SA-8 (Security and Privacy Engineering Principles) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-41080 affects libexpat versions prior to 2.8.0, where insufficient entropy in hash functions allows hash flooding through a crafted XML document. This vulnerability, classified under CWE-331 (Insufficient Entropy), enables denial-of-service conditions by degrading performance via hash table collisions. The CVSS v3.1 base score is 2.9 (AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L), reflecting low severity due to its local attack vector, high attack complexity, and limited impact on availability.
A local attacker with no privileges required can exploit this by supplying a malicious XML document to an application using the vulnerable libexpat library. The crafted input triggers hash flooding, causing excessive computation and partial denial of service, such as slowed processing or resource exhaustion in the affected component, without impacting confidentiality or integrity.
Advisories recommend upgrading to libexpat 2.8.0, which addresses the entropy issue as detailed in the release announcement on the hartwork blog, GitHub issue #47, pull request #1183, and oss-security mailing list posts from April 26, 2026. These resources confirm the fix improves hash randomization to prevent flooding attacks.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-23276
Vulnerability Data
libexpat before 2.8.0 uses insufficient entropy, and thus hash flooding can occur via a crafted XML document.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 6 hardening rules · 3 OS baselines
V6.5.2V11.3.4
Mitigating Controls (NIST 800-53 r5) AI
Key establishment and management requirements force use of approved RNG sources with adequate entropy when generating keys.
Security engineering principles can include selection of strong entropy sources during design.
Mandating approved cryptographic algorithms and modules inherently requires sufficient entropy for random values and keys.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices explicitly include vetted RNG and entropy sources, directly preventing this weakness while covering many other development concerns.
Password-strength policies implicitly require sufficient entropy, but the control addresses authentication rather than algorithmic randomness.
Proper encryption for data-at-rest requires sufficient entropy for keys/nonces; eliminating the weakness therefore supports but does not fully realize the control.
Cryptographic protection of data-in-transit depends on adequate entropy; the weakness directly undermines the control's effectiveness.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Mandates use of cryptography that must rely on sufficient entropy sources.
Security testing can detect insufficient-entropy defects before release.
Secure-SDLC activities include entropy validation during design and testing.
Secure-coding rules can explicitly forbid weak random-number generation.
Requires secure authentication mechanisms that depend on unpredictable secrets.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).
Oracle Linux 8 (2 rules)
- V-248524 OL 8 must implement NIST FIPS-validated cryptography for the following: To provision digital signatures, to generate cryptographic hashes, and to protect data requiring data-at-rest protections in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-331
- V-248563 The OL 8 SSH server must be configured to use strong entropy. prevents CWE-331
RHEL 7 (1 rule)
- V-204497 The Red Hat Enterprise Linux operating system must implement NIST FIPS-validated cryptography for the following: to provision digital signatures, to generate cryptographic hashes, and to protect data requiring data-at-rest protections in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-331
RHEL 8 (1 rule)
- V-230223 RHEL 8 must implement NIST FIPS-validated cryptography for the following: To provision digital signatures, to generate cryptographic hashes, and to protect data requiring data-at-rest protections in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-331