CVE-2024-39936Network attack vector

Request disclosure via premature HTTP/2 transmission

Published Jul 4, 2024 · Updated Nov 29, 2025

Certificate-validation bypass in Qt HTTP/2 before 5.15.18, 6.2.13, 6.5.7, or 6.7.3 allows remote attackers to disclose request data. QHttpNetworkConnectionChannel can dispatch multiplexed requests after emitting encrypted() but before a queued abort from that signal is processed. Exposure requires HTTP/2 and an application that rejects a redirected connection with a nonmatching TLS certificate; the reported consequence is request-data disclosure.

CVSS severity8.6
High
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Certificate-validation bypass in Qt HTTP/2 before 5.15.18, 6.2.13, 6.5.7, or 6.7.3 allows remote attackers to disclose request data. QHttpNetworkConnectionChannel can dispatch multiplexed requests after emitting encrypted() but before a queued abort from that signal is processed. Exposure requires HTTP/2 and an application that rejects a redirected connection with a nonmatching TLS certificate; the reported consequence is request-data disclosure.

The record

CVE
CVE-2024-39936
Published
Jul 4, 2024
Updated
Nov 29, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-367, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 4, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 29, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.9NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
8.6MITRE CNACVSS:3.1/AC:L/AV:N/A:N/C:H/I:N/PR:N/S:C/UI:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition
T1557Adversary-in-the-Middle

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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