Double free in FreeRDP async-update polygon handling
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Passive
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-415 and the CVSS impact.
Summary
FreeRDP from 3.29.0 before 3.32.0 contains a double free in the client's async-update message proxy, tracked as CWE-415. The proxy copies a parser-owned polygon points array without taking ownership, so both the queue consumer and parser cleanup free it. A malicious RDP server can send a point-bearing polygon order followed by a zero-point order to crash a client with +async-update enabled. A public exploit is linked in the references.
Written with Claude Haiku 5.5 from the sources below · 2026-10-27
Description from the CNA
FreeRDP 3.29.0 before 3.32.0 contains a double free in the client's async-update message proxy, which shallow-copies the parser-owned PolygonSC or PolygonCB points array when numPoints is zero, so both the queue consumer and parser cleanup free it. A malicious RDP server can send a point-bearing polygon order followed by a zero-point order to crash a client with +async-update enabled.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
Upgrade FreeRDP to 3.32.0, the fixed version.
Written with Claude Haiku 5.5 from the sources below · 2026-10-27
- Fix · CNA FreeRDP (FreeRDP) Fixed in 3.32.0
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
FreeRDP 3.32.0
20 records Highest priority Priority HIGH 1 HIGH, 15 MEDIUM, 4 LOW
Other records, highest priority first
- TI-2026-71718 Heap buffer over-read in FreeRDP proxy DRDYNVC channel name handlingPriority HIGH 70
- TI-2026-71714 Unbounded memory allocation in FreeRDP drive redirection readsPriority MEDIUM 64
- TI-2026-71713 Reachable assertion in FreeRDP lets a malicious server crash clientsPriority MEDIUM 64
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
Not affected: 5 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-13 Threatist record created from CVE-2026-109943
- 2026-10-13 Alias added: GHSA-5rf6-rg39-rmc3
- 2026-10-14 CISA SSVC decision points changed
- 2026-10-27 Affected versions changed · Red Hat
- 2026-10-27 CVSS score added · Red Hat
References
More Freerdp vulnerabilities
- TI-2026-85092 Use-after-free in FreeRDP rdpgfx channel close handling CVSS 4.0CRITICAL 9.3
- TI-2026-85091 Out-of-bounds write in FreeRDP proxy via bitmap cache v2 capability CVSS 4.0CRITICAL 9.3
- TI-2026-24435 FreeRDP has a `size_t` underflow in ADPCM decoder leads to heap-buffer-overflow write CVSS 3.1CRITICAL 9.8
- TI-2023-21373 Out-Of-Bounds Write in FreeRDP CVSS 3.1CRITICAL 9.8
- TI-2022-08692 Server side NTLM does not properly check parameters in FreeRDP CVSS 3.1CRITICAL 9.1
- TI-2023-21374 Out-Of-Bounds Read in FreeRDP CVSS 3.1CRITICAL 9.1
Sources
- CVE-2026-109943 · CVE Program
- CVE-2026-109943 · NVD
- FIRST EPSS
- GHSA-5rf6-rg39-rmc3 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-109943 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences