Description
A malicious or compromised HTTP/2 server withholding SETTINGS ACK can send RST_STREAM on a completed stream, planting a null pointer, and then send a PUSH_PROMISE for that stream, causing a null pointer dereference in the QNetworkAccessManager class of the Qt Network module that crashes the application.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| qt | qt | 6.8.0 – ≤ 6.8.9, 6.9.0 – ≤ 6.11.2 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | qt6-base | No fix yet | — |
| Debian 13 | qt6-base | No fix yet | — |
| Debian 12 | qt6-base | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | qt6-base | No fix yet | — |
| Ubuntu 26.04 LTS | qt6-base | No fix yet | — |
| Ubuntu 24.04 LTS | qt6-base | No fix yet | — |
| Ubuntu 22.04 LTS | qt6-base | No fix yet | — |
Advisories 1
- WID-SEC-2026-4098 QT: Schwachstelle ermöglicht Denial of Service BSI CERT-Bund (WID) · Oct 26, 2026