CVE-2025-5991

Memory corruption via HTTP/2 POST upload race

Published Jun 11, 2025 · Updated Jul 29, 2026

Use after free in Qt Framework 6.9.0 allows attackers to corrupt application memory via concurrent HTTP/2 POST and error processing. QHttp2ProtocolHandler races a QHttp2Stream body upload against error-response handling and accesses stream state after its lifetime ends. An affected application must upload a POST body over HTTP/2 while an error response is handled; ordinary HTTP is unaffected.

CVSS severity2.1
Low
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use after free in Qt Framework 6.9.0 allows attackers to corrupt application memory via concurrent HTTP/2 POST and error processing. QHttp2ProtocolHandler races a QHttp2Stream body upload against error-response handling and accesses stream state after its lifetime ends. An affected application must upload a POST body over HTTP/2 while an error response is handled; ordinary HTTP is unaffected.

The record

CVE
CVE-2025-5991
Published
Jun 11, 2025
Updated
Jul 29, 2026
Vendor
The Qt Company
Product
Qt Framework
Classifications
CWE-416
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 11, 2025CVE publishedPublication date reported by the CVE source.
  2. Jul 29, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=6.9.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

The Qt Company · Qt Frameworkversion=6.9.0

Published CVSS scores

7.5Amazon LinuxCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
2.1The Qt CompanyCVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L

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.

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No observations available

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

Weakness, pattern, technique

CWE-416Use After Free

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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