FreeRDP before 3.32.2 Heap Buffer Overflow via Early User Authorization Read
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. Affected FreeRDP versions are 3.32.1 and earlier (fixed in 3.32.2). The malicious or compromised RDP server must complete PROTOCOL_HYBRID_EX CredSSP with the FreeRDP client. The client is the asynchronous client that keeps the partially filled receive stream.
- 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
- Severity7.2/10CVSS 7.2
- 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-2026-121962 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 7.2 (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- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean?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, the open-source Remote Desktop Protocol client library, contains a heap buffer overflow in its handling of Early User Authorization reads during CredSSP hybrid connections. A malicious RDP server can reach it remotely without logging in, but the client user must connect to that server, and the attack can corrupt memory on the client, enabling a crash or denial of service that could also affect data integrity.
Read the original description
FreeRDP before 3.32.2 contains a heap buffer overflow in transport_default_read_pdu when handling partial Early User Authorization reads during PROTOCOL_HYBRID_EX CredSSP. A malicious RDP server can split the four-byte EUA result into short reads that advance the stream pointer beyond the 16 KiB allocation, causing an out-of-bounds write and client denial of service.
What to do
Check whether your setup matches what the bug needs.
Affected FreeRDP versions are 3.32.1 and earlier (fixed in 3.32.2). The malicious or compromised RDP server must complete PROTOCOL_HYBRID_EX CredSSP with the FreeRDP client. The client is the asynchronous client that keeps the partially filled receive stream.Upgrade 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.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-121962
Is CVE-2026-121962 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 or compromised RDP server that completes the PROTOCOL_HYBRID_EX CredSSP handshake with a FreeRDP client can cause an out-of-bounds write on the heap. The result is a heap buffer overflow that crashes the client, a denial of service.Source: vulncheck.com, github.com
Which versions are affected by CVE-2026-121962?
FreeRDP: before 3.32.2.Source: cve.now feed data
Am I affected, and how do I check?
FreeRDP 3.32.1 and earlier are affected. The bug needs the asynchronous client, which keeps a partially filled receive stream, and an RDP server that completes PROTOCOL_HYBRID_EX CredSSP with it. To check a version, run the FreeRDP client with its version option (for example xfreerdp /version) and compare the result with 3.32.2.Source: vulncheck.com, github.com
How do I fix CVE-2026-121962?
Upgrade FreeRDP to 3.32.2 or later, which contains the fix.Source: vulncheck.com, github.com