Buffer overflow in Freerdp
CVE-2026-23530
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.21.0,`freerdp_bitmap_decompress_planar` does not validate `nSrcWidth`/`nSrcHeight` against `planar->maxWidth`/`maxHeight` before RLE decode. 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.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.005 (42.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 42nd percentile — 42.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: +0.001
Affected products
- Freerdp — versions < 3.21.0
Weakness classification (CWE)
References
- github.com/FreeRDP/FreeRDP/security/advisories/GHSA-r4hv-852m-fq7p (Exploit, Vendor Advisory)
- github.com/FreeRDP/FreeRDP/blob/38514dfa5813aa945a86cfbcec279033f8394468/libfre… (Product)
- github.com/FreeRDP/FreeRDP/blob/38514dfa5813aa945a86cfbcec279033f8394468/libfre… (Product)
- github.com/FreeRDP/FreeRDP/blob/38514dfa5813aa945a86cfbcec279033f8394468/libfre… (Product)
- github.com/FreeRDP/FreeRDP/releases/tag/3.21.0 (Release Notes)
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Frequently asked questions
- What is CVE-2026-23530?
- CVE-2026-23530 is a critical-severity vulnerability in Freerdp, classified under Heap-based Buffer Overflow. CVSS score: 9.8/10. Published 2026-01-19.
- How severe is CVE-2026-23530?
- Critical severity. CVSS v3 base score is 9.8 out of 10.