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CVE-2026-109940

MEDIUM 5.1 PoC AVAILABLE

Published 2026-10-13 · Last modified 2026-10-13

FreeRDP 3.0.0-beta1 before 3.32.0 on Unix builds with PKCS#11 support has a stack-based buffer overflow in wprintKeyName() in WinPR's NCrypt PKCS#11 provider. It hex-encodes a key's CKA_ID, which can be up to 64 bytes, into a fixed 128-byte stack buffer. An attacker supplying a malicious PKCS#11 token or module whose key and matching certificate use a 55- to 64-byte CKA_ID can overflow the client's stack during key enumeration, causing a crash.

EXPLOIT AVAILABLE

Public exploit or PoC code exists. Modeled probability is still low, but the barrier to attack is reduced — watch closely.

Exploitation likelihood

0.1%chance of exploitation in 30 days · 4th percentile

○ In CISA KEV ● Public exploit / PoC

Impact if exploited

5.1CVSS 4.0 · MEDIUM

  • ConfidentialityNone
  • IntegrityNone
  • AvailabilityHigh

What an attacker needs

  • ⚠Access: Requires physical access to the device
  • ✓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

Test against your own equipment

curl -s https://vulnpedia.com/cve/CVE-2026-109940/poc.jsonMachine-readable PoC index for this CVE (for automation).

Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-109940/poc.json

Affected

Vendors Freerdp

Products Freerdp

Weakness (CWE)

  • CWE-121: Stack-based Buffer Overflow

CVSS vector

CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

All CVSS metrics

  • MEDIUM 5.1 v4.0 · CNA Primary
    CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
  • MEDIUM 4.3 v3.1 · CNA Primary
    CVSS:3.1/AV:P/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
  • MEDIUM 5.1 v4.0 · NVD Secondary
    CVSS:4.0/AV:P/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 4.3 v3.1 · NVD Primary
    CVSS:3.1/AV:P/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

References

Exploits & PoC

Advisories

Sources: NVD · CVE.org · EPSS