Out-of-bounds read in Qt NTLM authentication handling
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Active
- Attack complexity
- Low
- Attack requirements
- Present
- Impact type
- —
- Confidentiality · integrity · availability
- High · None · High
- Fix status
- Partial Red Hat: 6 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat.
Summary
Qt versions from 6.8.0 before 6.8.10 and from 6.9.0 before 6.11.2 are affected in the Qt Network module. The QAuthenticator NTLM authentication handling contains an out-of-bounds read (CWE-125). A remote attacker operating a malicious server or proxy can send a crafted NTLM challenge to obtain heap memory contents or crash an application that authenticates with NTLM through QNetworkAccessManager or QTcpSocket.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Description from the CNA
Out-of-bounds read in the QAuthenticator NTLM authentication handling in the Qt Network module in Qt Group Qt allows remote attackers to obtain sensitive information (heap memory contents) or cause a denial of service (application crash) via a crafted NTLM challenge sent by a malicious server or proxy, when an application using QNetworkAccessManager or QTcpSocket authenticates with NTLM.
Why it matters now
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
Remediation
Upgrade Qt to 6.8.10 or 6.11.2. Red Hat lists Red Hat Enterprise Linux 6 with no fix planned, and Red Hat Enterprise Linux 7, 8, 9 and 10 and Red Hat Hardened Images with no fix available.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
- Fix · CNA qt (qt) Fixed in 6.8.10, 6.11.2
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 Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat Hardened Images | Affected | No fix yet |
Timeline
- 2026-10-27 Threatist record created from CVE-2026-105946
- 2026-10-27 Alias added: GHSA-99v5-r742-mrm9
- 2026-11-04 CISA SSVC decision points changed
- 2026-11-06 Affected versions changed · Red Hat
- 2026-11-06 CVSS score added · Red Hat
References
More qt vulnerabilities
- 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
Sources
- CVE-2026-105946 · CVE Program
- CVE-2026-105946 · NVD
- FIRST EPSS
- GHSA-99v5-r742-mrm9 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-105946 · Red Hat security data · CC BY 4.0
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