Cyber Resilience

CVE-2026-76956

Published
20 August 2026
Modified
20 August 2026
CVSS Score v3.1 5.9
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0025 16th percentile
Risk Priority 45 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-76956 is a medium-severity Unexpected Status Code or Return Value (CWE-394) vulnerability. Its CVSS base score is 5.9 (Medium).

Operationally, ranked at the 16th 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 SA-11 (Developer Testing and Evaluation) and SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A10:2025 Mishandling of Exceptional Conditions

EU & UK References

Vulnerability Data

In libexpat 2.8.2 and 2.8.3 before 2.8.4, misinterpretation of getentropy's return code leads to insufficient entropy, which results in being vulnerable to hash flooding attacks, causing a denial of service via crafted XML content.

CWE(s)
CWE-394

Related Threats

CVEs Like This One

CVE-2025-12515Shared CWE-394
CVE-2025-48510Shared CWE-394
CVE-2025-12516Shared CWE-394
CVE-2025-22854Shared CWE-394
CVE-2025-23013Shared CWE-394
CVE-2026-25085Shared CWE-394
CVE-2023-25948Shared CWE-394
CVE-2024-1713Shared CWE-394
CVE-2023-28975Shared CWE-394
CVE-2023-48429Shared CWE-394

Affected Assets

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation at post-design stages will find missing or incorrect checks for unexpected but valid return values.

SA-15 Development Process, Standards, and Tools partial match

Requiring documented development standards and tools can mandate exhaustive checking of all function return values.

SA-8 Security and Privacy Engineering Principles partial match

Engineering principles such as defensive programming and complete return-value checking stop the weakness from being introduced in code.

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.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require proper validation of all function return values and status codes.

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.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing can detect missing checks for unexpected but valid return values.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle requires handling of all return values and status codes.

A.8.26 Application security requirements partial match
prevents

Application security requirements include proper validation of function results and error conditions.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly mandate checking all legitimate return values and status codes.

References