FreeRDP before 3.32.2 Shadow Server Denial of Service via remdesk Channel
FreeRDP shadow servers before 3.32.2, in default assertion-enabled builds, can abort when an authenticated client joins the remdesk channel. Fixed in 3.32.2.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 3.32.2
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. Attacker must be an authenticated client that joins the remdesk static virtual channel of a FreeRDP shadow server The remdesk channel is enabled on the server only after an authenticated client joins it Affects default assertion-enabled shadow-server builds
- Exploitation?/40Exploitation: unknown (data gap). No CISA SSVC exploitation rating yet
- Exposure8/25Specific setups only, reachable over the network
- 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 65 if added to CISA KEV
- Would score about 60 if CISA's SSVC rates exploitation active
- Would score about 22 if CISA's SSVC rates it automatable
CVE-2026-121407 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- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean?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? →
- 15/100 · 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
Summary
FreeRDP before 3.32.2 contains a denial of service vulnerability in the shadow server's remdesk_server_thread that allows authenticated clients to crash the process via an inverted PDU length check. Attackers can send an 8192-byte remdesk payload declaring an eight-byte PDU length to trigger a fatal Stream_Seek assertion, aborting the server and dropping sessions.
What to do
Check whether your setup matches what the bug needs.
Attacker must be an authenticated client that joins the remdesk static virtual channel of a FreeRDP shadow server The remdesk channel is enabled on the server only after an authenticated client joins it Affects default assertion-enabled shadow-server buildsUpgrade to a fixed version: 3.32.2.
Timeline
- CVE published
- First seen by cve.now
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-2026-121407
Is CVE-2026-121407 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. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
An authenticated RDP client that joins the remdesk static virtual channel can make a FreeRDP shadow-server process abort, which drops its sessions. This is a denial of service.Source: github.com, vulncheck.com
Which versions are affected by CVE-2026-121407?
FreeRDP: before 3.32.2.Source: cve.now feed data
Am I affected, and how do I check?
The listed range is FreeRDP versions before 3.32.2. The issue affects default assertion-enabled shadow-server builds, and the server enables remdesk only after an authenticated client joins it. Check the FreeRDP version installed and whether the shadow server is built and running.Source: github.com, vulncheck.com
How do I fix CVE-2026-121407?
Upgrade FreeRDP to 3.32.2 or later. The facts list no workaround.Source: github.com, vulncheck.com