ClearCodec · Prior to version 3.21.0,
Affects freerdpSource GCVE Database
Not known to be exploited · CVSS 9.8 Critical · fixed in 2.2.0+dfsg1-0ubuntu0.18.04.4+esm3 : patch freerdp as a priority.
Data as of 27 Oct 2026, 06:42 UTC
- Patch
- Available – fixed in 2.2.0+dfsg1-0ubuntu0.18.04.4+esm3, 2.6.1+dfsg1-0ubuntu0.20.04.2+esm1, 2.6.1+dfsg1-3ubuntu2.8 +3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 19 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Patches and advisories
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 25.10freerdp3pkg:deb/ubuntu/freerdp3?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSfreerdp3pkg:deb/ubuntu/freerdp3?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu Pro 24.04 LTSfreerdp2pkg:deb/ubuntu/freerdp2?arch=source&distro=esm-apps/nobleOther threats | Affected
| Fixed in
|
Ubuntu 22.04 LTSfreerdp2pkg:deb/ubuntu/freerdp2?arch=source&distro=jammyOther threats | Affected
| Fixed in
|
Ubuntu Pro 20.04 LTSfreerdp2pkg:deb/ubuntu/freerdp2?arch=source&distro=esm-infra/focalOther threats | Affected
| Fixed in
|
Ubuntu Pro 18.04 LTSfreerdp2pkg:deb/ubuntu/freerdp2?arch=source&distro=esm-infra/bionicOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.21.0, in ClearCodec, when `glyphData` is present, `clear_decompress` calls `freerdp_image_copy_no_overlap` without validating the destination rectangle, allowing an out-of-bounds read/write via crafted RDPGFX surface updates. 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.
References
- ubuntu.com/security/CVE-2026-23531 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-23531 (opens in a new tab)
- github.com/FreeRDP/FreeRDP/security/advisories/GHSA-xj5h-9cr5-23c5 (opens in a new tab)
- github.com/FreeRDP/FreeRDP/blob/38514dfa5813aa945a86cfbcec279033f8394468/libfreerdp/codec/clear.c (opens in a new tab)
- github.com/FreeRDP/FreeRDP/releases/tag/3.21.0 (opens in a new tab)
- ubuntu.com/security/notices/USN-8004-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8105-1 (opens in a new tab)