FreeRDP 3.0.0 before 3.32.2 Denial of Service via RemoteFX Region Assertion
Affects FreeRDP 3.0.0 through 3.32.1 clients built with verbose WinPR assertions that negotiate RemoteFX with a malicious server. Fixed in 3.32.2.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- Proof of concept public, per CISA
- Fix
- Fixed in 3.32.2
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. Client was built with verbose WinPR assertions (WITH_VERBOSE_WINPR_ASSERT=ON) Client negotiates RemoteFX with the malicious server Affected FreeRDP releases from 3.0.0 through 3.32.1
- 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
- Severity7.1/10CVSS 7.1
- No patch0/5No signal
What would change the score
- Would score about 69 if added to CISA KEV
- Would score about 64 if CISA's SSVC rates exploitation active
CVE-2026-121393 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 7.1 (high) and affects FreeRDP; fixed in 3.32.2.
- 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- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean?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? →
- 34/100 · 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
- Fix
- Fixed in 3.32.2
- 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: partial
Summary
FreeRDP, an open-source Remote Desktop Protocol client library, is affected by this vulnerability. A malicious remote desktop server can send specially crafted graphics data that causes a connecting client built with verbose WinPR assertions to crash, resulting in a denial of service.
Read the original description
FreeRDP from 3.0.0 before 3.32.2 contains a denial of service vulnerability that allows malicious RDP servers to abort clients built with verbose WinPR assertions by sending crafted RemoteFX region rectangles. Attackers can supply a rectangle with x set to 65535 alongside a SurfaceBits destination left of 1, triggering a 16-bit coordinate assertion in rfx_process_message that terminates the client process.
What to do
Check whether your setup matches what the bug needs.
Client was built with verbose WinPR assertions (WITH_VERBOSE_WINPR_ASSERT=ON) Client negotiates RemoteFX with the malicious server Affected FreeRDP releases from 3.0.0 through 3.32.1Upgrade to a fixed version: 3.32.2.
Timeline
- CVE published
- First seen by cve.now
- CISA SSVC assessment
Exploitation: poc · Automatable: no · Technical impact: partial
- Record last updated
Affected versions
- FreeRDP FreeRDP
From 3.0.0 · fixed in 3.32.2
Evidence 2
- Advisory
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-121393
Is CVE-2026-121393 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?
A malicious server can abort a connecting FreeRDP client process during RemoteFX negotiation by triggering a WinPR assertion failure. The result is loss of the client's availability (denial of service).Source: github.com, vulncheck.com
Which versions are affected by CVE-2026-121393?
FreeRDP: from 3.0.0 before 3.32.2.Source: cve.now feed data
Am I affected, and how do I check?
FreeRDP 3.0.0 through 3.32.1 is affected, but only clients built with WITH_VERBOSE_WINPR_ASSERT=ON that negotiate RemoteFX with a server. To check, look at the installed FreeRDP version and whether that build option was enabled when the client was compiled.Source: github.com, vulncheck.com
How do I fix CVE-2026-121393?
Upgrade to FreeRDP 3.32.2 or later, which contains the fix.Source: github.com, vulncheck.com