Buffer overflow in Freerdp
CVE-2026-121958
FreeRDP through 3.32.1 has a heap out-of-bounds write in the RDPGFX client because the delete_surface callback truncates surface hash keys to 16 bits, leaving the surface table inconsistent so HashTable_GetKeys writes past its allocated key array. A malicious or man-in-the-middle RDP server can exploit this by creating surfaceId 0xFFFF, closing the RDPGFX channel, sending repeated DELETESURFACE PDUs, and then sending ENDFRAME or RESETGRAPHICS.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/FreeRDP/FreeRDP/security/advisories/GHSA-m59q-wm7v-mp57 (Exploit, vendor-advisory, Mitigation, Vendor Advisory)
- www.vulncheck.com/advisories/freerdp-through-3.32.1-heap-out-of-bounds-write-vi… (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-121958?
- CVE-2026-121958 is a high-severity vulnerability in Freerdp, classified under Heap-based Buffer Overflow. CVSS score: 8.8/10. Published 2026-11-04.
- How severe is CVE-2026-121958?
- High severity. CVSS v3 base score is 8.8 out of 10.