NULL pointer dereference in FreeRDP Cache Bitmap V3 order processing
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: 1 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-476.
Summary
FreeRDP from 3.27.1 before 3.32.0 contains a NULL pointer dereference (CWE-476) in Cache Bitmap V3 order handling. The client bitmap cache is accessed before it is initialized during connection setup. A malicious or compromised RDP server can send a Cache Bitmap V3 order to crash a connecting client that has enabled the non-default Bitmap Cache V3 feature. A public exploit is linked in the references, but the flaw is not listed in CISA KEV.
Written with Claude Haiku 5.5 from the sources below · 2026-10-27
Description from the CNA
FreeRDP 3.27.1 before 3.32.0 contains a NULL pointer dereference in update_read_cache_bitmap_v3_order() in libfreerdp/core/orders.c, which accesses the client bitmap cache when the CBR3_DO_NOT_CACHE flag is set, even though the cache is not yet initialized before Demand Active. A malicious or compromised RDP server can send a Cache Bitmap V3 order during connection setup to crash a connecting client that has enabled the non-default Bitmap Cache V3 feature (/cache:codec:<rfx|nsc|jpeg>).
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
Update FreeRDP to version 3.32.0, which fixes the flaw. Red Hat lists Red Hat Enterprise Linux 10 as affected with no fix available.
Written with Claude Haiku 5.5 from the sources below · 2026-10-27
- Fix · CNA FreeRDP (FreeRDP) Fixed in 3.32.0
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Release ·
FreeRDP 3.32.0
20 records Highest priority Priority HIGH 1 HIGH, 15 MEDIUM, 4 LOW
Other records, highest priority first
- TI-2026-71718 Heap buffer over-read in FreeRDP proxy DRDYNVC channel name handlingPriority HIGH 70
- TI-2026-71714 Unbounded memory allocation in FreeRDP drive redirection readsPriority MEDIUM 64
- TI-2026-71713 Reachable assertion in FreeRDP lets a malicious server crash clientsPriority MEDIUM 64
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 |
Not affected: 4 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-13 Threatist record created from CVE-2026-109939
- 2026-10-13 Alias added: GHSA-93pr-x2pm-jv23
- 2026-10-13 CISA SSVC decision points changed
- 2026-10-13 Priority changed: MEDIUM → LOW
- 2026-10-27 Affected versions changed · Red Hat
- 2026-10-27 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-2026-109939 · CVE Program
- CVE-2026-109939 · NVD
- FIRST EPSS
- GHSA-93pr-x2pm-jv23 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-109939 · Red Hat security data · CC BY 4.0
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