CVE-2026-91947
HIGH 7.7 ALL-YEARSFreeRDP server versions before 3.31.0 contain a use-after-free vulnerability in the DRDYNVC parser that dereferences a channel pointer after releasing the synchronization lock. Authenticated clients can race AUDIN channel closure messages against DRDYNVC data parsing to trigger heap-use-after-free when accessing freed channel objects.
Severe if exploited (CVSS 7.7), but no confirmed exploitation. Patch on a normal cadence.
Exploitation likelihood
0.3%chance of exploitation in 30 days · 22nd percentile
Impact if exploited
7.7CVSS 4.0 · HIGH · CNA
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityHigh
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ⚠Privileges: Requires a low-privilege account
- ✓User interaction: No user interaction needed
- ⚠Complexity: Needs a race window or specific setup
- ⚠Requirements: Specific conditions must be present
✓ 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-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
CVSS vector
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
All CVSS metrics
- HIGH 7.7 v4.0 · CNA Primary
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N - HIGH 7.5 v3.1 · CNA Primary
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H - HIGH 7.7 v4.0 · NVD Secondary
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/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 - HIGH 7.5 v3.1 · NVD Secondary
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H