CVE-2025-5991
Use after free in QHttp2ProtocolHandler
There is a "Use After Free" vulnerability in Qt's QHttp2ProtocolHandler in the QtNetwork module. This only affects HTTP/2 handling, HTTP handling is not affected by this at all. This happens due to a race condition between how QHttp2Stream uploads the body of a POST request and the simultaneous handling of HTTP error responses.
This issue only affects Qt 6.9.0 and has been fixed for Qt 6.9.1.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
Use after free in QHttp2ProtocolHandler
There is a "Use After Free" vulnerability in Qt's QHttp2ProtocolHandler in the QtNetwork module. This only affects HTTP/2 handling, HTTP handling is not affected by this at all. This happens due to a race condition between how QHttp2Stream uploads the body of a POST request and the simultaneous handling of HTTP error responses.
This issue only affects Qt 6.9.0 and has been fixed for Qt 6.9.1.
- Record
CVE-2025-5991- CVSS 4.0
- 2.1 Low
CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L - Weakness
- CWE-416
- Updated
- 2026-11-02
EUVDEUVD-2025-18092
There is a "Use After Free" vulnerability in Qt's QHttp2ProtocolHandler in the QtNetwork module. This only affects HTTP/2 handling, HTTP handling is not affected by this at all. This happens due to a race condition between how QHttp2Stream uploads the body of a POST request and the simultaneous handling of HTTP error responses.
This issue only affects Qt 6.9.0 and has been fixed for Qt 6.9.1.
- Record
EUVD-2025-18092- CVSS 4.0
- 2.1 Low
CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-xv5c-vg59-hj7x
There is a "Use After Free" vulnerability in Qt's QHttp2ProtocolHandler in the QtNetwork module....
There is a "Use After Free" vulnerability in Qt's QHttp2ProtocolHandler in the QtNetwork module. This only affects HTTP/2 handling, HTTP handling is not affected by this at all. This happens due to a race condition between how QHttp2Stream uploads the body of a POST request and the simultaneous handling of HTTP error responses.
This issue only affects Qt 6.9.0 and has been fixed for Qt 6.9.1.
- Record
GHSA-xv5c-vg59-hj7x- CVSS 4.0
- 2.1 Low
CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Weakness
- CWE-416
- Updated
- 2026-11-02
NVD
There is a "Use After Free" vulnerability in Qt's QHttp2ProtocolHandler in the QtNetwork module. This only affects HTTP/2 handling, HTTP handling is not affected by this at all. This happens due to a race condition between how QHttp2Stream uploads the body of a POST request and the simultaneous handling of HTTP error responses.
This issue only affects Qt 6.9.0 and has been fixed for Qt 6.9.1.
- Record
CVE-2025-5991- CVSS 4.0
- 2.1 Low
CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Weakness
- CWE-416
- Updated
- 2026-11-02
OSVUBUNTU-CVE-2025-5991
There is a "Use After Free" vulnerability in Qt's QHttp2ProtocolHandler in the QtNetwork module. This only affects HTTP/2 handling, HTTP handling is not affected by this at all. This happens due to a race condition between how QHttp2Stream uploads the body of a POST request and the simultaneous handling of HTTP error responses. This issue only affects Qt 6.9.0 and has been fixed for Qt 6.9.1.
- Record
UBUNTU-CVE-2025-5991- CVSS 4.0
- 2.1 Low
CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L - Updated
- 2026-11-02
OSV No score
There is a "Use After Free" vulnerability in Qt's QHttp2ProtocolHandler in the QtNetwork module. This only affects HTTP/2 handling, HTTP handling is not affected by this at all. This happens due to a race condition between how QHttp2Stream uploads the body of a POST request and the simultaneous handling of HTTP error responses.
This issue only affects Qt 6.9.0 and has been fixed for Qt 6.9.1.
- Record
CVE-2025-5991- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
qtbase-opensource-src-glesUbuntu:16.04:LTS |
All versions, plus listed versions 5.4.2+dfsg-2ubuntu95.5.1+dfsg-6ubuntu15.5.1+dfsg-10ubuntu15.5.1+dfsg-13ubuntu15.5.1+dfsg-13ubuntu2 Show 9 moreShow less5.5.1+dfsg-13ubuntu35.5.1+dfsg-14ubuntu15.5.1+dfsg-14ubuntu25.5.1+dfsg-14ubuntu35.5.1+dfsg-15ubuntu15.5.1+dfsg-16ubuntu15.5.1+dfsg-16ubuntu45.5.1+dfsg-16ubuntu55.5.1+dfsg-16ubuntu6 |
None known |
qtbase-opensource-src-glesUbuntu:20.04:LTS |
All versions, plus listed versions 5.12.4+dfsg-1build15.12.5+dfsg-15.12.5+dfsg-25.12.8+dfsg-0ubuntu1 |
None known |
qt6-baseUbuntu:22.04:LTS |
All versions, plus listed versions 6.2.2+dfsg-5ubuntu16.2.2+dfsg-6ubuntu16.2.2+dfsg-6ubuntu26.2.4+dfsg-1ubuntu16.2.4+dfsg-2ubuntu16.2.4+dfsg-2ubuntu1.1 |
None known |
qtbase-opensource-src-glesUbuntu:22.04:LTS |
All versions, plus listed versions 5.15.2+dfsg-45.15.2+dfsg-55.15.3+dfsg-1 |
None known |
qt6-baseUbuntu:24.04:LTS |
All versions, plus listed versions 6.4.2+dfsg-186.4.2+dfsg-196.4.2+dfsg-19build16.4.2+dfsg-206.4.2+dfsg-216.4.2+dfsg-21.1build46.4.2+dfsg-21.1build5 |
None known |
qtbase-opensource-src-glesUbuntu:24.04:LTS |
All versions, plus listed versions 5.15.10+dfsg-25.15.10+dfsg-35.15.12+dfsg-15.15.12+dfsg-1ubuntu15.15.12+dfsg-1ubuntu25.15.13+dfsg-1 |
None known |
qt6-baseUbuntu:25.10 |
All versions, plus listed versions 6.8.3+dfsg-0ubuntu26.8.3+dfsg-0ubuntu36.9.2+dfsg-1ubuntu1 |
None known |
qtbase-opensource-src-glesUbuntu:25.10 |
All versions, plus listed versions 5.15.15+dfsg-25.15.17+dfsg-1 |
None known |
qt6-baseUbuntu:26.10 |
All versions, plus listed versions 6.10.2+dfsg-76.10.2+dfsg-14ubuntu26.10.2+dfsg-156.10.2+dfsg-166.11.2+dfsg-4ubuntu2 |
None known |
qtbase-opensource-src-glesUbuntu:26.10 |
All versions, plus listed versions 5.15.18+dfsg-15.15.19+dfsg-2 |
None known |
qt6-baseUbuntu:26.04:LTS |
All versions, plus listed versions 6.9.2+dfsg-1ubuntu16.9.2+dfsg-26.9.2+dfsg-3ubuntu16.9.2+dfsg-3ubuntu26.9.2+dfsg-46.10.2+dfsg-36.10.2+dfsg-66.10.2+dfsg-7 |
None known |
qtbase-opensource-src-glesUbuntu:26.04:LTS |
All versions, plus listed versions 5.15.17+dfsg-15.15.17+dfsg-25.15.18+dfsg-1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected | ||
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-5991 is a low vulnerability (CVSS 2.1) in Qt, published June 11, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.14%, the 3rd percentile. No source names a fixed version.