Security Resilience

CVE-2024-1556

Mozilla Firefox ≤ 123.0

Published
20 February 2024
Modified
17 June 2026
Patch / advisory
CVSS Score v3.1 6.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
EPSS Score 0.0047 40th percentile
Risk Priority 50 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-2024-1556 is a medium-severity Improper Check for Unusual or Exceptional Conditions (CWE-754) vulnerability in Mozilla Firefox. Its CVSS base score is 6.5 (Medium).

Operationally, ranked at the 40th 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 SI-10 (Information Input Validation) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

The incorrect object was checked for NULL in the built-in profiler, potentially leading to invalid memory access and undefined behavior. *Note:* This issue only affects the application when the profiler is running. This vulnerability affects Firefox < 123.

CWE(s)

Related Threats

CVEs Like This One

CVE-2026-4713Same product: Mozilla Firefox
CVE-2026-4714Same product: Mozilla Firefox
CVE-2026-4708Same product: Mozilla Firefox
CVE-2026-4709Same product: Mozilla Firefox
CVE-2026-4706Same product: Mozilla Firefox
CVE-2026-4707Same product: Mozilla Firefox
CVE-2026-4685Same product: Mozilla Firefox
CVE-2026-4693Same product: Mozilla Firefox
CVE-2026-4695Same product: Mozilla Firefox
CVE-2026-4719Same product: Mozilla Firefox

Affected Assets

mozilla
firefox
≤ 123.0

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

Developer testing and evaluation explicitly exercises unusual conditions to find missing or incorrect checks.

Input validation directly requires checking for unexpected or malformed conditions before they propagate.

Security engineering principles include structured handling of edge cases and exceptions during design.

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.8.15 Logging partial match
finds

Logging can record unhandled exceptions but does not prevent the weakness itself.

finds

Monitoring may detect symptoms of unhandled conditions but does not eliminate the root weakness.

blocks

Secure development life cycle mandates exception handling and input validation that directly prevent missing checks for unusual conditions.

blocks

Application security requirements explicitly call for handling of exceptional conditions and error paths.

blocks

A.8.27 mandates security-by-design principles (fail securely, least privilege, distrust external input, security-oriented design reviews) that reach some but not most CWE-754 cases; many exceptional-condition checks live in low-level code paths outside architecture-level engineering.

prevents

Secure coding standards directly mandate proper checks for exceptional and unusual conditions.

Hardening callouts derived

DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.

  • No fine-grained STIG row for CWE-754, a class-level weakness. Rules are authored against its narrower children: CWE-354.

References