CRITICAL: CVE-2026-23533 (CVSS 9.8) — freerdp freerdp
CVE: CVE-2026-23533
CVSS: 9.8 (3.1) — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Severity: CRITICAL
Status: Critical advisory
Affected
- freerdp freerdp
Summary
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.21.0, a client-side heap buffer overflow occurs in the RDPGFX ClearCodec decode path when maliciously crafted residual data causes out-of-bounds writes during color output. A malicious server can trigger a client‑side heap buffer overflow, causing a crash (DoS) and potential heap corruption with code‑execution risk depending on allocator behavior and surrounding heap layout. Version 3.21.0 contains a patch for the issue.
Verified Sources
References
- https://github.com/FreeRDP/FreeRDP/blob/38514dfa5813aa945a86cfbcec279033f8394468/libfreerdp/codec/clear.c#L268-L281
- https://github.com/FreeRDP/FreeRDP/blob/38514dfa5813aa945a86cfbcec279033f8394468/libfreerdp/codec/clear.c#L336
- https://github.com/FreeRDP/FreeRDP/releases/tag/3.21.0
- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-32q9-m5qr-9j2v
- https://access.redhat.com/errata/RHSA-2026:2048
- https://access.redhat.com/errata/RHSA-2026:2081
- https://access.redhat.com/errata/RHSA-2026:2222
- https://access.redhat.com/errata/RHSA-2026:2714
- https://access.redhat.com/errata/RHSA-2026:2736
- https://access.redhat.com/errata/RHSA-2026:2770
_Validated by the Lyrie Threat Intelligence Pipeline — 3 independent sources confirmed before publication. No speculation._
Lyrie Verdict
A vulnerability of this severity is exactly what Lyrie's anti-rogue-AI defense is built for: continuous, autonomous monitoring that doesn't wait for human reaction time.
Validated sources
- [1]NVD
- [2]GitHub Advisory
- [3]MITRE