CVE-2024-39936VulnerabilityPublished 4 Jul 2024Updated 29 Nov 2025

CVE-2024-39936: qtbase · n/a

Affects qtbaseSource CVE Database V5

Not known to be exploited · CVSS 8.6 High · fixed in 6.7.3 : patch qtbase soon.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

8.6High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.4% chance of exploitation in 30 days – higher than 41% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 6.7.3, 6.5.7, 6.2.13 +1

CVSS:3.1/AC:L/AV:N/A:N/C:H/I:N/PR:N/S:C/UI:N

Attack Complexity: Low
Attack Vector: Network
Availability: None
Confidentiality: High
Integrity: None
Privileges Required: None
Scope: Changed
User Interaction: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Availability: None: There is no impact to availability within the impacted component.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 4 Jul 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade org.qtproject/qtbase to 6.7.3, 6.5.7, 6.2.13 or 5.15.18.

Affected software

Product	Affected	Fixed in
Mavenorg.qtproject/qtbase`pkg:maven/org.qtproject/qtbase`Other threats	Affected <5.15.18 <6.2.13 >=6.3 <6.5.7 >=6.6 <6.7.3	Fixed in 5.15.18 6.2.13 6.5.7 6.7.3

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

1. 2. Conduct an inventory of all applications and devices using Qt HTTP/2 functionality to identify exposure. 3. Review application code and configurations to ensure that security-relevant decisions are not made before the encrypted() signal or equivalent TLS handshake completion indicators are processed. 4. Implement network-level protections such as Web Application Firewalls (WAFs) that can detect anomalous HTTP/2 traffic patterns potentially exploiting timing issues. 5. Employ TLS inspection and logging to monitor encrypted traffic for suspicious activity, while respecting privacy and compliance requirements. 6. For embedded or IoT devices using Qt, coordinate with vendors to ensure firmware updates are available and deployed. 7. Increase security awareness among development teams about TOCTOU race conditions and secure signal handling in asynchronous frameworks like Qt. 8. Consider temporary mitigations such as disabling HTTP/2 support in Qt-based applications if patching is delayed and risk is high. 9. Perform penetration testing and code reviews focused on connection security state management to detect similar timing vulnerabilities. 10. Maintain incident response readiness to quickly address any exploitation attempts once patches are deployed.

Description

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() signal has not yet been emitted and processed..

Impact

For European organizations, the impact of CVE-2024-39936 can be substantial due to the widespread adoption of Qt in various sectors including automotive, telecommunications, industrial control, and enterprise software. Confidentiality breaches could lead to exposure of sensitive customer data, intellectual property, or internal communications. Given the vulnerability allows remote exploitation without authentication or user interaction, attackers could leverage this flaw to intercept or manipulate encrypted HTTP/2 traffic, undermining trust in secure communications. This could result in regulatory non-compliance under GDPR if personal data is compromised, leading to financial penalties and reputational damage. Critical infrastructure and embedded systems using Qt for secure communication may also be at risk, potentially affecting operational continuity. The high CVSS score and the scope of affected Qt versions indicate a broad attack surface, increasing the likelihood of targeted attacks against European organizations that rely on Qt-based applications. The absence of known exploits currently provides a window for proactive mitigation, but also suggests attackers may develop exploits soon.

CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition (opens in a new tab)
Base weaknessLikelihood of exploit: Medium
The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.
Implementation
The most basic advice for TOCTOU vulnerabilities is to not perform a check before the use. This does not resolve the underlying issue of the execution of a function on a resource whose state and identity cannot be assured, but it does help to limit the false sense of security given by the check.
Implementation
When the file being altered is owned by the current user and group, set the effective gid and uid to that of the current user and group when executing this statement.
Architecture and Design
Limit the interleaving of operations on files from multiple processes.
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
OWASP ASVS 4.0.3
V1.11.3 (opens in a new tab)
V11.1.6 (opens in a new tab)
V1.11.2 (opens in a new tab)
Attack patterns
Leveraging Race Conditions via Symbolic Links (opens in a new tab)
Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 29 Nov 2025, 13:12 UTC

WeaknessesCWE-367

Technical details

References

Community reviews

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