FreeRDP through 3.32.1 Heap Out-of-Bounds Write via RDPGFX HashTable_GetKeys
FreeRDP 3.32.1 and earlier are affected, with the bug triggered in the default client connection flow. No fix is listed in the checked facts.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- Proof of concept public, per CISA
- Fix
- No fix listed
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. Affects FreeRDP 3.32.1 and earlier Triggered within the default client connection flow
- Exploitation15/40CISA rates a proof of concept as public
- Exposure12/25Specific setups only, reachable over the network without a login
- Reach?/20Reach: unknown (data gap). No tracked technology or package matched
- Severity9.7/10CVSS 8.7, total technical impact per CISA
- No patch5/5No patch listed yet
What would change the score
- Would score about 77 if added to CISA KEV
- Would score about 72 if CISA's SSVC rates exploitation active
CVE-2026-121958 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 8.7 (high) and affects FreeRDP; no fixed version is listed yet.
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- Published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 42/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: poc
- Automatable: no
- Technical impact: total
Summary
FreeRDP, a remote desktop client library, contains a heap out-of-bounds write that a malicious or man-in-the-middle RDP server could trigger against a connecting client. The attack is reachable remotely without logging in but requires the victim to take an action, such as connecting to the server.
Read the original description
FreeRDP through 3.32.1 has a heap out-of-bounds write in the RDPGFX client because the delete_surface callback truncates surface hash keys to 16 bits, leaving the surface table inconsistent so HashTable_GetKeys writes past its allocated key array. A malicious or man-in-the-middle RDP server can exploit this by creating surfaceId 0xFFFF, closing the RDPGFX channel, sending repeated DELETESURFACE PDUs, and then sending ENDFRAME or RESETGRAPHICS.
What to do
Check whether your setup matches what the bug needs.
Affects FreeRDP 3.32.1 and earlier Triggered within the default client connection flowWorkaround: The checked facts list no workaround. Check the FreeRDP advisory for any mitigation published while no fixed release exists.
Timeline
- CVE published
- First seen by cve.now
- CISA SSVC assessment
Exploitation: poc · Automatable: no · Technical impact: total
- Record last updated
Affected versions
- FreeRDP FreeRDP
through 3.32.1
Evidence 2
- Advisory
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-121958
Is CVE-2026-121958 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: cve.now feed data
What does this mean?
The bug is a heap out-of-bounds write in the FreeRDP client process, reached through the RDPGFX HashTable_GetKeys code during the default connection flow. It can reliably crash the client, and it may allow remote code execution, though that is not proven.Source: vulncheck.com, github.com
Which versions are affected by CVE-2026-121958?
FreeRDP: through 3.32.1.Source: cve.now feed data
Am I affected, and how do I check?
FreeRDP 3.32.1 and earlier are affected, and the bug is triggered within the default client connection flow. To check an installation, compare its FreeRDP version number with 3.32.1.Source: vulncheck.com, github.com
How do I fix CVE-2026-121958?
The checked facts do not name a fixed version, so no upgrade target can be given from them. Check the FreeRDP project's advisory for a release newer than 3.32.1 and install it when available.Source: vulncheck.com, github.com
What if there's no patch?
The checked facts list no workaround. Check the FreeRDP advisory for any mitigation published while no fixed release exists.Source: vulncheck.com, github.com