CPU exhaustion in FreeRDP RDG control packet handling
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Passive
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 5 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-835.
Summary
FreeRDP before 3.32.2 contains a denial of service flaw in rdg_process_control_packet caused by a loop with no reachable exit condition (CWE-835). A malicious RD Gateway can exhaust client CPU by sending an incomplete keepalive control packet after completing the RDG tunnel open exchange, which keeps one client thread spinning at full CPU.
Written with Claude Haiku 5.5 from the sources below · 2026-11-04
Description from the CNA
FreeRDP before 3.32.2 contains a denial-of-service vulnerability in rdg_process_control_packet that allows a malicious RD Gateway to exhaust client CPU by sending an incomplete keepalive control packet. Attackers completing the RDG tunnel-open exchange then send an eight-byte header with packetLength 0xFFFF and withhold the body, causing an unbounded no-progress read loop that spins one client thread at full CPU.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
Upgrade FreeRDP to version 3.32.2, which fixes this flaw. The sources list no fixed version for Red Hat Enterprise Linux 6, 7, 8, 9 and 10.
Written with Claude Haiku 5.5 from the sources below · 2026-11-04
- Fix · CNA FreeRDP (FreeRDP) Fixed in 3.32.2
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
FreeRDP 3.32.2
27 records Highest priority Priority HIGH 3 HIGH, 11 MEDIUM, 13 LOW
Other records, highest priority first
- TI-2026-84268 Denial of service in FreeRDP WinPR PNG and JPEG image readersPriority HIGH 77
- TI-2026-84291 Denial of service in FreeRDP via oversized X.224 routing tokenPriority HIGH 69
- TI-2026-84280 Use-after-free in FreeRDP dyn-channel-dump modulePriority HIGH 69
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-11-03 Threatist record created from CVE-2026-121400
- 2026-11-03 Alias added: GHSA-4c29-wc44-6c3g
- 2026-11-03 CISA SSVC decision points changed
- 2026-11-03 Priority changed: MEDIUM → LOW
- 2026-11-04 Affected versions changed · Red Hat
- 2026-11-04 CVSS score added · Red Hat
References
More Freerdp vulnerabilities
- TI-2026-85092 Use-after-free in FreeRDP rdpgfx channel close handling CVSS 4.0CRITICAL 9.3
- TI-2026-85091 Out-of-bounds write in FreeRDP proxy via bitmap cache v2 capability CVSS 4.0CRITICAL 9.3
- TI-2026-24435 FreeRDP has a `size_t` underflow in ADPCM decoder leads to heap-buffer-overflow write CVSS 3.1CRITICAL 9.8
- TI-2023-21373 Out-Of-Bounds Write in FreeRDP CVSS 3.1CRITICAL 9.8
- TI-2022-08692 Server side NTLM does not properly check parameters in FreeRDP CVSS 3.1CRITICAL 9.1
- TI-2023-21374 Out-Of-Bounds Read in FreeRDP CVSS 3.1CRITICAL 9.1
Sources
- CVE-2026-121400 · CVE Program
- CVE-2026-121400 · NVD
- FIRST EPSS
- GHSA-4c29-wc44-6c3g · GitHub Advisory Database · CC BY 4.0
- CVE-2026-121400 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences