Cyber Resilience

CVE-2024-1563

Race Condition in Mozilla Firefox Focus ≤ 122.0

Race Condition
Published
22 February 2024
Modified
17 June 2026
Patch / advisory
View advisory
CVSS Score v3.1 8.1
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0039 32th percentile
Risk Priority 59 floored blend · peak EPSS

Summary

CVE-2024-1563 is a high-severity Time-of-check Time-of-use (TOCTOU) Race Condition (CWE-367) vulnerability in Mozilla Firefox Focus. Its CVSS base score is 8.1 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Path Interception (T1034); ranked at the 32th 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 AC-25 (Reference Monitor) and AC-3 (Access Enforcement) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

An attacker could have executed unauthorized scripts on top origin sites using a JavaScript URI when opening an external URL with a custom Firefox scheme and a timeout race condition. This vulnerability affects Focus for iOS < 122.

CWE(s)
CWE-367

Related Threats

MITRE ATT&CK Enterprise Techniques

T1034 Path Interception Persistence
**This technique has been deprecated.
attack.mitre.org →
T1548 Abuse Elevation Control Mechanism Privilege Escalation
Adversaries may circumvent mechanisms designed to control privilege elevation to gain higher-level permissions.
attack.mitre.org →
T1574 Hijack Execution Flow Stealth
Adversaries may execute their own malicious payloads by hijacking the way operating systems run programs.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-10474Same product: Mozilla Firefox Focus
CVE-2024-26284Same product: Mozilla Firefox Focus
CVE-2024-5022Same product: Mozilla Firefox Focus
CVE-2024-6601Same vendor: Mozilla
CVE-2024-8399Same product: Mozilla Firefox Focus
CVE-2024-7531Same vendor: Mozilla
CVE-2024-0605Same product: Mozilla Firefox Focus
CVE-2024-0606Same product: Mozilla Firefox Focus
CVE-2025-10290Same product: Mozilla Firefox Focus
CVE-2025-3859Same product: Mozilla Firefox Focus

Affected Assets

mozilla
firefox focus
≤ 122.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V15.4.2
  • V17.2.6

Mitigating Controls (NIST 800-53 r5) AI

AC-25 Reference Monitor good match

A reference monitor that is always invoked and analyzable structurally eliminates the non-atomic check-then-use pattern underlying TOCTOU.

AC-3 Access Enforcement partial match

Access enforcement that performs an atomic check-and-use decision directly stops the window in which a TOCTOU race can be exploited.

SC-39 Process Isolation partial match

Process isolation limits the blast radius of a successful TOCTOU exploitation but does not remove the race itself.

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 include coding standards and reviews that prevent TOCTOU race conditions.

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.8.17 Clock synchronization none match
none

Reliable, synchronized time across systems narrows the exploitable window in which a resource state can change between a security check and its use.

References