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Out-of-bounds write in FreeRDP proxy via bitmap cache v2 capability

Priority HIGH 81CWE-787Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Code execution
Confidentiality · integrity · availability
High · High · 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-787 and the CVSS impact.

Summary

FreeRDP before 3.32.2 has an out-of-bounds write in its proxy (CWE-787). The bitmap cache v2 capability check rejects only cell cache counts above 5, yet the cell array is accessed at fixed indices 0 through 4, so a client declaring fewer than five caches causes writes past the array. A remote client connecting to the proxy can exploit this without authentication to corrupt the heap, leak heap data to the backend, or crash the proxy. A public exploit is linked in the references.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

FreeRDP before 3.32.2 has an out-of-bounds write in the proxy because rdp_read_bitmap_cache_v2_capability_set rejects only numCellCaches values above 5, yet the bitmap cache v2 cell array is later accessed at fixed indices 0 through 4. A client connecting to the proxy can declare fewer than five cell caches in its Confirm Active, causing heap corruption, heap data leakage to the backend, or a crash.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00503 43rd percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial FreeRDP (FreeRDP): 3.32.2Red Hat: 1 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
FreeRDPFreeRDPbefore 3.32.23.32.2Patch availableCNA
  • FreeRDP VendorFreeRDP Affected before 3.32.2 Fixed in 3.32.2 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:*before 3.32.2VulnerableFreeRDP
  • cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:* Versions before 3.32.2 Vulnerable ·FreeRDP

Remediation

Upgrade FreeRDP to version 3.32.2, 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 · 2026-11-06

  • 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

    14 records Highest priority Priority HIGH 11 HIGH, 3 MEDIUM

    Other records, highest priority first

    • TI-2026-85092 Use-after-free in FreeRDP rdpgfx channel close handlingPriority HIGH 81
    • TI-2026-85103 Heap buffer overflow in FreeRDP RD Gateway RPC clientPriority HIGH 77
    • TI-2026-85099 Unauthenticated denial of service in FreeRDP via CredSSP TSRequestPriority HIGH 77

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 10AffectedNo fix yet
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

  1. 2026-11-04 Threatist record created from CVE-2026-121952
  2. 2026-11-04 Alias added: GHSA-9gqr-m6pm-p7q7
  3. 2026-11-04 CISA SSVC decision points changed
  4. 2026-11-04 Priority changed: MEDIUM → HIGH
  5. 2026-11-06 Affected versions changed · Red Hat
  6. 2026-11-06 CVSS score added · Red Hat

References

  • TI-2026-85092 Use-after-free in FreeRDP rdpgfx channel close handling 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
  • TI-2026-85103 Heap buffer overflow in FreeRDP RD Gateway RPC client CVSS 4.0HIGH 8.7
See all 336 →

Sources