Bug 2559852
| Summary: | CVE-2026-93521 tigervnc: xorg-x11-server: Privilege escalation via crafted RandR provider property requests [fedora-44] | ||
|---|---|---|---|
| Product: | [Fedora] Fedora | Reporter: | Marian Rehak <mrehak> |
| Component: | tigervnc | Assignee: | Jan Grulich <jgrulich> |
| Status: | ON_QA --- | QA Contact: | Fedora Extras Quality Assurance <extras-qa> |
| Severity: | high | Docs Contact: | |
| Priority: | high | ||
| Version: | 44 | CC: | jgrulich |
| Target Milestone: | --- | Keywords: | Security, SecurityTracking |
| Target Release: | --- | ||
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
| Whiteboard: | {"flaws": ["b2b6ed6e-3f0a-454a-833f-fc342908eaaf"]} | ||
| Fixed In Version: | Doc Type: | --- | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | Type: | --- | |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
| Bug Depends On: | |||
| Bug Blocks: | 2545164 | ||
FEDORA-2026-6b7d3e80f7 (tigervnc-1.16.2-9.fc44) has been submitted as an update to Fedora 44. https://bodhi.fedoraproject.org/updates/FEDORA-2026-6b7d3e80f7 FEDORA-2026-80450b1573 (tigervnc-1.16.2-9.fc45) has been submitted as an update to Fedora 45. https://bodhi.fedoraproject.org/updates/FEDORA-2026-80450b1573 FEDORA-2026-6b7d3e80f7 has been pushed to the Fedora 44 testing repository. Soon you'll be able to install the update with the following command: `sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-6b7d3e80f7` You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-6b7d3e80f7 See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates. FEDORA-2026-80450b1573 has been pushed to the Fedora 45 testing repository. Soon you'll be able to install the update with the following command: `sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-80450b1573` You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-80450b1573 See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates. |
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process. RRChangeProviderProperty() has two bugs in the PropModePrepend case: 1. new_value.size is set to 'len' (the new data length) instead of 'total_len' (len + prop_value->size), losing track of the existing data. This also affects PropModeAppend. 2. The old_data offset is computed using prop_value->size instead of len. For PrependMode, the layout should be [new(len)][old(size)], so old_data should start at len * size_in_bytes. These bugs are analogous to the ones fixed in RRChangeOutputProperty(), see commit 541ab2ecd41d ("Xi/randr: fix handling of PropModeAppend/Prepend"). This vulnerability was discovered by: Anonymous working with TrendAI Zero Day Initiative ZDI-CAN-31944