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TI-2026-18958 Aliases CVE-2026-23534

FreeRDP has heap-buffer-overflow in clear_decompress_bands_data

Priority HIGH 73CWE-122Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 12 fixed, 1 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-122 and the CVSS impact.

Summary

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.21.0, a client-side heap buffer overflow occurs in the ClearCodec bands decode path when crafted band coordinates allow writes past the end of the destination surface buffer. A malicious server can trigger a client‑side heap buffer overflow, causing a crash (DoS) and potential heap corruption with code‑execution risk depending on allocator behavior and surrounding heap layout. Version 3.21.0 contains a patch for the issue.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00533 45th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial FreeRDP (FreeRDP): 3.21.0Red Hat: 6 advisoriesRed Hat: 12 fixed, 1 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
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

VendorProductAffected versionsFixed inStatusSource
FreeRDPFreeRDPbefore 3.21.03.21.0Patch availableCNA
  • FreeRDP VendorFreeRDP Affected before 3.21.0 Fixed in 3.21.0 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:*before 3.21.0VulnerableFreeRDP
  • cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:* Versions before 3.21.0 Vulnerable ·FreeRDP

Remediation

  • Fix · CNA FreeRDP (FreeRDP) Fixed in 3.21.0

Red Hat 6 advisories

  • RHSA-2026:3037 Released 2026-02-23 · Red Hat rating Important
    freerdp security update
    • Red Hat CodeReady Linux Builder EUS (v.9.6) freerdp-devel-2:2.11.7-1.el9_6.1, libwinpr-devel-2:2.11.7-1.el9_6.1
    • Red Hat Enterprise Linux AppStream EUS (v.9.6) freerdp-2:2.11.7-1.el9_6.1, freerdp-libs-2:2.11.7-1.el9_6.1, libwinpr-2:2.11.7-1.el9_6.1
  • RHSA-2026:2952 Released 2026-02-18 · Red Hat rating Important
    freerdp security update
    • Red Hat Enterprise Linux AppStream EUS (v. 10.0) freerdp-2:3.10.3-3.el10_0.1, freerdp-libs-2:3.10.3-3.el10_0.1, libwinpr-2:3.10.3-3.el10_0.1
    • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) freerdp-devel-2:3.10.3-3.el10_0.1, freerdp-server-2:3.10.3-3.el10_0.1, libwinpr-devel-2:3.10.3-3.el10_0.1
  • RHSA-2026:2736 Released 2026-02-16 · Red Hat rating Important
    freerdp security update
    • Red Hat CodeReady Linux Builder EUS (v.9.4) freerdp-devel-2:2.11.2-1.el9_4.1, libwinpr-devel-2:2.11.2-1.el9_4.1
    • Red Hat Enterprise Linux AppStream EUS (v.9.4) freerdp-2:2.11.2-1.el9_4.1, freerdp-libs-2:2.11.2-1.el9_4.1, libwinpr-2:2.11.2-1.el9_4.1
Show 3 more Red Hat advisories
  • RHSA-2026:2222 Released 2026-02-09 · Red Hat rating Important
    freerdp security update
    • Red Hat Enterprise Linux AppStream (v. 10) freerdp-2:3.10.3-5.el10_1.1, freerdp-libs-2:3.10.3-5.el10_1.1, libwinpr-2:3.10.3-5.el10_1.1
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) freerdp-devel-2:3.10.3-5.el10_1.1, freerdp-server-2:3.10.3-5.el10_1.1, libwinpr-devel-2:3.10.3-5.el10_1.1
  • RHSA-2026:2081 Released 2026-02-05 · Red Hat rating Important
    freerdp security update
    • Red Hat Enterprise Linux AppStream (v. 8) freerdp-2:2.11.7-2.el8_10, freerdp-libs-2:2.11.7-2.el8_10, libwinpr-2:2.11.7-2.el8_10 +1
    • Red Hat Enterprise Linux CRB (v. 8) freerdp-devel-2:2.11.7-2.el8_10
  • RHSA-2026:2048 Released 2026-02-05 · Red Hat rating Important
    freerdp security update
    • Red Hat Enterprise Linux AppStream (v. 9) freerdp-2:2.11.7-1.el9_7.1, freerdp-libs-2:2.11.7-1.el9_7.1, libwinpr-2:2.11.7-1.el9_7.1
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) freerdp-devel-2:2.11.7-1.el9_7.1, libwinpr-devel-2:2.11.7-1.el9_7.1

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix planned: Will not fix
Red Hat CodeReady Linux Builder EUS (v.9.4)Fixed RHSA-2026:2736
Red Hat CodeReady Linux Builder EUS (v.9.6)Fixed RHSA-2026:3037
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:2222
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2026:2081
Red Hat Enterprise Linux AppStream (v. 9)Fixed RHSA-2026:2048
Red Hat Enterprise Linux AppStream EUS (v. 10.0)Fixed RHSA-2026:2952
Red Hat Enterprise Linux AppStream EUS (v.9.4)Fixed RHSA-2026:2736
Red Hat Enterprise Linux AppStream EUS (v.9.6)Fixed RHSA-2026:3037
Red Hat Enterprise Linux CRB (v. 8)Fixed RHSA-2026:2081
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:2222
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9)Fixed RHSA-2026:2048
Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0)Fixed RHSA-2026:2952
Not affected: 1 product
  • Red Hat Enterprise Linux 7

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-23534

References

Exploit 1

Other 3

  • 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
See all 336 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences