CVE-2026-91951
HIGH 7.1 ALL-YEARSFreeRDP versions before 3.31.0 contain an out-of-bounds write vulnerability in the urbdrc client channel's urb_send_current_frame_number_result() function. A malicious RDP server can send a crafted 28-byte USB redirection message to trigger a 4-byte write past the allocated 16-byte buffer, causing denial of service when verbose asserts are enabled.
Severe if exploited (CVSS 7.1), but no confirmed exploitation. Patch on a normal cadence.
Exploitation likelihood
0.4%chance of exploitation in 30 days · 30th percentile
Impact if exploited
7.1CVSS 4.0 · HIGH · CNA
- ConfidentialityNone
- IntegrityNone
- AvailabilityHigh
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ✓Privileges: No account or privileges required
- ⚠User interaction: Succeeds with passive user activity
- ✓Complexity: No special conditions — reliably repeatable
- ✓Requirements: No special attack requirements
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept & exploit code
No public exploit or proof-of-concept code is catalogued for this CVE (no ExploitDB, Nuclei, or CISA-KEV entry). It may still exist — search GitHub or check the references below.
Weakness (CWE)
- CWE-617: Reachable Assertion
CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Known Affected Software Configurations
| Vendor | Product | Version range |
|---|---|---|
| Freerdp | Freerdp | ≥ 3.14.0 and < 3.31.0 |
All CVSS metrics
- HIGH 7.1 v4.0 · CNA Primary
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N - MEDIUM 6.5 v3.1 · CNA Primary
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - HIGH 7.1 v4.0 · NVD Secondary
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - MEDIUM 6.5 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H