Out-of-bounds write in FreeRDP proxy via bitmap cache v2 capability
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 1 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-787 and the CVSS impact.
Summary
FreeRDP before 3.32.2 has an out-of-bounds write in its proxy (CWE-787). The bitmap cache v2 capability check rejects only cell cache counts above 5, yet the cell array is accessed at fixed indices 0 through 4, so a client declaring fewer than five caches causes writes past the array. A remote client connecting to the proxy can exploit this without authentication to corrupt the heap, leak heap data to the backend, or crash the proxy. A public exploit is linked in the references.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Description from the CNA
FreeRDP before 3.32.2 has an out-of-bounds write in the proxy because rdp_read_bitmap_cache_v2_capability_set rejects only numCellCaches values above 5, yet the bitmap cache v2 cell array is later accessed at fixed indices 0 through 4. A client connecting to the proxy can declare fewer than five cell caches in its Confirm Active, causing heap corruption, heap data leakage to the backend, or a crash.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Total
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 version 3.32.2, which fixes the flaw. Red Hat lists Red Hat Enterprise Linux 10 as affected with no fix available.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
- Fix · CNA FreeRDP (FreeRDP) Fixed in 3.32.2
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
FreeRDP 3.32.2
14 records Highest priority Priority HIGH 11 HIGH, 3 MEDIUM
Other records, highest priority first
- TI-2026-85092 Use-after-free in FreeRDP rdpgfx channel close handlingPriority HIGH 81
- TI-2026-85103 Heap buffer overflow in FreeRDP RD Gateway RPC clientPriority HIGH 77
- TI-2026-85099 Unauthenticated denial of service in FreeRDP via CredSSP TSRequestPriority HIGH 77
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet |
Not affected: 4 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-11-04 Threatist record created from CVE-2026-121952
- 2026-11-04 Alias added: GHSA-9gqr-m6pm-p7q7
- 2026-11-04 CISA SSVC decision points changed
- 2026-11-04 Priority changed: MEDIUM → HIGH
- 2026-11-06 Affected versions changed · Red Hat
- 2026-11-06 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-2026-24435 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
- TI-2026-85103 Heap buffer overflow in FreeRDP RD Gateway RPC client CVSS 4.0HIGH 8.7
Sources
- CVE-2026-121952 · CVE Program
- CVE-2026-121952 · NVD
- FIRST EPSS
- GHSA-9gqr-m6pm-p7q7 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-121952 · 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