Cyber Resilience

CVE-2024-39936

Race Condition in Qt ≤ 5.15.18

Race Condition
Published
04 July 2024
Modified
29 November 2025
Patch / advisory
View advisory
CVSS Score v3.1 8.6
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
EPSS Score 0.0049 40th percentile
Risk Priority 62 floored blend · peak EPSS

Summary

CVE-2024-39936 is a high-severity Time-of-check Time-of-use (TOCTOU) Race Condition (CWE-367) vulnerability in Qt Qt. Its CVSS base score is 8.6 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Path Interception (T1034); 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 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 issue was discovered in HTTP2 in Qt before 5.15.18, 6.x before 6.2.13, 6.3.x through 6.5.x before 6.5.7, and 6.6.x through 6.7.x before 6.7.3. Code to make security-relevant decisions about an established connection may execute too early, because the encrypted()…

more

signal has not yet been emitted and processed..

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-2023-24607Same product: Qt Qt
CVE-2025-30348Same product: Qt Qt
CVE-2023-33285Same product: Qt Qt
CVE-2025-5683Same product: Qt Qt
CVE-2024-30161Same product: Qt Qt
CVE-2023-38197Same product: Qt Qt
CVE-2024-25580Same product: Qt Qt
CVE-2023-32763Same product: Qt Qt
CVE-2023-28075Shared CWE-367
CVE-2024-1563Shared CWE-367

Affected Assets

qt
qt
≤ 5.15.18 · 6.0.0 — 6.2.13 · 6.3.0 — 6.5.7

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