Cyber Resilience

CVE-2024-5699

Mozilla Firefox ≤ 127.0

Public PoC
Published
11 June 2024
Modified
04 April 2025
Patch / advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0077 52th percentile
Risk Priority 72 floored blend · peak EPSS

Summary

CVE-2024-5699 is a critical-severity Improper Handling of Case Sensitivity (CWE-178) vulnerability in Mozilla Firefox. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Masquerading (T1036); ranked in the top 48% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to AC-24 (Access Control Decisions) and AC-3 (Access Enforcement) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

In violation of spec, cookie prefixes such as `__Secure` were being ignored if they were not correctly capitalized - by spec they should be checked with a case-insensitive comparison. This could have resulted in the browser not correctly honoring the…

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behaviors specified by the prefix. This vulnerability affects Firefox < 127.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1036 Masquerading Stealth
Adversaries may attempt to manipulate features of their artifacts to make them appear legitimate or benign to users and/or security tools.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-10941Same product: Mozilla Firefox
CVE-2023-28160Same product: Mozilla Firefox
CVE-2026-15718Same product: Mozilla Firefox
CVE-2026-16395Same product: Mozilla Firefox
CVE-2026-16408Same product: Mozilla Firefox
CVE-2025-13018Same product: Mozilla Firefox
CVE-2025-49710Same product: Mozilla Firefox
CVE-2026-4700Same product: Mozilla Firefox
CVE-2023-5173Same product: Mozilla Firefox
CVE-2025-5271Same product: Mozilla Firefox

Affected Assets

mozilla
firefox
≤ 127.0

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

Applying access control decisions to each request depends on accurate property determination that accounts for case differences.

Correct enforcement of authorizations for resource access structurally requires consistent case-sensitive handling of identifiers to avoid incorrect decisions.

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 partial match
prevents

Secure SDLC practices can catch and prevent case-sensitivity flaws during code review or testing, but fixing one CWE achieves negligible coverage of the broad control.

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.

prevents

Secure SDLC practices should include case-sensitivity requirements in design and coding standards.

prevents

Application security requirements must specify case handling for identifiers and paths.

prevents

Architecture principles should enforce canonical, case-aware resource naming.

prevents

Secure coding guidelines must mandate explicit case handling to prevent inconsistent lookups.

degrades

Access-control rules that ignore case can allow unintended resource access.

degrades

Authentication logic must treat identifiers consistently to avoid bypass via case differences.

References