# CVE-2026-121952: FreeRDP out-of-bounds write in bitmap cache v2 capability

Source: https://junglewise.ai/threats/cve-2026-121952-freerdp-before-3-32-2-has-an-out-of-bounds-write-in-the-proxy  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-04. Updated: 2026-11-04  
License: CC BY 4.0 with a link back

CVE-2026-121952 · Severity: critical · CVSS 9.8 · Published 2026-11-04

FreeRDP is a remote desktop protocol implementation widely used in terminal servers and proxy solutions. The proxy component fails to validate client-supplied bitmap cache cell counts, allowing an unauthenticated remote attacker to trigger heap memory corruption, crash the proxy process, or leak sensitive heap data to the backend server.

Technologies: [FreeRDP](https://junglewise.ai/threats/technologies/freerdp). Vendors: [FreeRDP](https://junglewise.ai/threats/vendors/freerdp).

## Quick answers

**Is CVE-2026-121952 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-121952 being exploited in the wild.

**How severe is CVE-2026-121952?** Critical severity, with a CVSS score of 9.8, published 4 November 2026.

**Which products and versions are affected?** FreeRDP before 3.32.2.

**Is there a fix for CVE-2026-121952?** Yes: fixed in 3.32.2. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-121952 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-121952?** Check whether you run FreeRDP at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 3.32.2

## Technical details

The vulnerability exists in rdp_read_bitmap_cache_v2_capability_set, which only rejects numCellCaches values greater than 5, accepting values 0–4. However, downstream code unconditionally accesses the bitmap cache array at fixed indices 0–4, causing out-of-bounds reads and writes when fewer than five cells are declared. An attacker connecting to the proxy's listening port and completing X.224/MCS/GCC handshakes up to the Confirm Active message can trigger a 4-byte heap write, heap data leakage, or null pointer dereference.

## Affected products

- FreeRDP FreeRDP before 3.32.2

## Timeline

- 2026-10-20: disclosed
- 2026-11-04: advisory

## References

- [https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-xc85-4mqc-xgcx](https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-xc85-4mqc-xgcx)
- [https://www.vulncheck.com/advisories/freerdp-before-3.32.2-proxy-out-of-bounds-write-via-bitmap-cache-v2-capability](https://www.vulncheck.com/advisories/freerdp-before-3.32.2-proxy-out-of-bounds-write-via-bitmap-cache-v2-capability)

## Related threats

- [FreeRDP heap use-after-free in brush cache](https://junglewise.ai/threats/cve-2026-125394-freerdp-before-3-33-0-contains-a-heap-use-after-free)
- [FreeRDP heap buffer overflow in RD Gateway RPC client](https://junglewise.ai/threats/cve-2026-121964-freerdp-before-3-32-2-contains-a-heap-based-buffer-overflow-in)
- [FreeRDP use-after-free in dynamic rdpsnd channel](https://junglewise.ai/threats/cve-2026-121963-freerdp-before-3-32-2-contains-a-use-after-free-vulnerability-in)
- [FreeRDP denial of service in NLA shadow server via malformed TSRequest](https://junglewise.ai/threats/cve-2026-121960-freerdp-before-3-32-2-contains-a-denial-of-service-vulnerability)
- [FreeRDP heap out-of-bounds write in RDPGFX HashTable_GetKeys](https://junglewise.ai/threats/cve-2026-121958-freerdp-through-3-32-1-has-a-heap-out-of-bounds-write-in-the)