TI-2026-79626 Aliases CVE-2026-95620 GHSA-qcfg-4m2w-6vm7

Use-after-free in Qt HTTP/2 client lets servers crash applications

LOW 11CWE-416Published 2026-10-23 · Updated 2026-11-02

Key facts

Attack vector: Network
Privileges required: None
User interaction: Active
Attack complexity: High
Attack requirements: Present
Impact type: Denial of service
Confidentiality · integrity · availability: None · None · High
Fix status: Partial Red Hat: 2 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-416 and the CVSS impact.

Summary

Qt versions from 6.9.0 before 6.11.3 are affected in the Qt Network module. A use-after-free flaw (CWE-416) in the QNetworkAccessManager HTTP/2 client support lets a malicious or compromised HTTP/2 server crash the client application. The impact is on availability.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

A use-after-free vulnerability in the Qt QNetworkAccessManager HTTP/2 client support of the Qt Network module allows a malicious or compromised HTTP/2 server to cause the client application to crash, affecting availability.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00229 13th percentileScored 2026-11-07

Fix Partial qt (qt): 6.11.3Red Hat: 2 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
qt	qt	6.9.0 to before 6.11.3	6.11.3	Patch available	CNA

qt Vendorqt Affected 6.9.0 to before 6.11.3 Fixed in 6.11.3 Patch available CNA

Remediation

Update Qt to 6.11.3, the fixed version. The sources list no fixed version: Red Hat reports none available for Red Hat Enterprise Linux 10 and Red Hat Hardened Images.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Fix · CNA qt (qt) Fixed in 6.11.3

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Product	Status	Plan or fix
Red Hat Enterprise Linux 10	Affected	No fix yet: Fix deferred
Red Hat Hardened Images	Affected	No fix yet

Timeline

2026-10-23 Threatist record created from CVE-2026-95620
2026-10-23 Alias added: GHSA-qcfg-4m2w-6vm7
2026-11-02 CISA SSVC decision points changed
2026-11-06 Affected versions changed · Red Hat
2026-11-06 CVSS score added · Red Hat

References

Patch 1

https://codereview.qt-project.org/c/qt/qtbase/+/759717

Advisory 1

https://wiki.qt.io/List_of_known_vulnerabilities_in_Qt_products#CVE-2026-95620:

TI-2024-23902 QAbstractOAuth in Qt Network Authorization in Qt before 5.15.17, 6.x before 6.2.13, 6.3.x… CVSS 3.1CRITICAL 9.8
TI-2022-21359 Heap-based buffer overflow in Qt CVSS 3.1HIGH 8.8
TI-2022-19524 Integer overflow in Qt CVSS 3.1HIGH 8.8
TI-2023-18997 In Qt before 5.15.15, 6.x before 6.2.9, and 6.3.x through 6.5.x before 6.5.2, there can… CVSS 3.1HIGH 7.5
TI-2021-09305 Integer Overflow vulnerability in qsvghandler.cpp in Qt qtsvg versions 5.15.1, 6.0.0… CVSS 3.1MEDIUM 5.5
TI-2023-28356 An issue was discovered in the HTTP2 implementation in Qt before 5.15.17, 6.x before… CVSS 3.1CRITICAL 9.8

See all 106 →

Sources

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