FreeRDP before 3.32.2 Infinite Loop via Truncated WebSocket Frame
All FreeRDP versions before 3.32.2 are affected, including RDG WebSocket use, which is enabled by default. 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. FreeRDP versions before 3.32.2 are affected RDG WebSocket use is enabled by default in settings The client must accept the gateway's certificate (for example with /cert:ignore) for a MITM to succeed
- 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-2026-121959 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- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean?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, a remote desktop client library, is affected by an infinite loop bug in its WebSocket handling that lets a malicious RD Gateway make the client spin and consume CPU until it is killed. An attacker can reach it remotely without logging in, but the victim must take some action, such as connecting to the malicious gateway.
Read the original description
FreeRDP before 3.32.2 contains an infinite loop vulnerability in websocket_context_read that fails to handle a zero BIO result with payload outstanding. A malicious RD Gateway can send a truncated WebSocket frame followed by a TLS close_notify, causing a client thread to spin and consume CPU until killed.
What to do
Check whether your setup matches what the bug needs.
FreeRDP versions before 3.32.2 are affected RDG WebSocket use is enabled by default in settings The client must accept the gateway's certificate (for example with /cert:ignore) for a MITM to succeedUpgrade 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
fixed in 3.32.2
Evidence 2
- Advisory
- Link
Corrections
None so far.
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Questions about CVE-2026-121959
Is CVE-2026-121959 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 truncated WebSocket frame makes a FreeRDP client thread loop endlessly and consume CPU until the process is killed, which is a denial of service. The advisory reports no memory corruption or data exposure in its testing.Source: vulncheck.com, github.com
Which versions are affected by CVE-2026-121959?
FreeRDP: before 3.32.2.Source: cve.now feed data
Am I affected, and how do I check?
FreeRDP versions before 3.32.2 are affected. The bug involves RDG WebSocket use, which is enabled by default in settings, and a man-in-the-middle attack additionally requires the client to accept the gateway's certificate, for example with /cert:ignore. To check, compare the installed FreeRDP version with 3.32.2 and check whether RDG WebSocket is in use.Source: vulncheck.com, github.com
How do I fix CVE-2026-121959?
Upgrade FreeRDP to 3.32.2 or later. The facts list no workaround.Source: vulncheck.com, github.com