CVE-2026-23534
FreeRDP is a free implementation of the Remote Desktop Protocol.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.46%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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 ClearCodec bands decode path when crafted band coordinates allow writes past the end of the destination surface buffer. 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.
- CVSS 4.0
- 7.7 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.46% probability · 39th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-122
- Affected
- freerdp/freerdp
- Source
- security-advisories@github.com
References
- https://github.com/FreeRDP/FreeRDP/blob/38514dfa5813aa945a86cfbcec279033f8394468/libfreerdp/codec/clear.c#L878-L879Product
- https://github.com/FreeRDP/FreeRDP/blob/38514dfa5813aa945a86cfbcec279033f8394468/libfreerdp/codec/clear.c#L883-L884Product
- https://github.com/FreeRDP/FreeRDP/releases/tag/3.21.0Release Notes
- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-3frr-mp8w-4599Exploit, Vendor Advisory
- 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-2026:2736
- https://access.redhat.com/errata/RHSA-2026:2952
- https://access.redhat.com/errata/RHSA-2026:3037
- https://access.redhat.com/security/cve/CVE-2026-23534
- https://bugzilla.redhat.com/show_bug.cgi?id=2430888
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-23534.json
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.