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TI-2026-21011 Aliases CVE-2026-25997

FreeRDP has heap-use-after-free in xf_clipboard_format_equal

Priority MEDIUM 64CWE-416Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
None · None · Low
Fix status
Partial Red Hat: 4 fixed, 2 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat.

Summary

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, `xf_clipboard_format_equal` reads freed `lastSentFormats` memory because `xf_clipboard_formats_free` (called from the cliprdr channel thread during auto-reconnect) frees the array while the X11 event thread concurrently iterates it in `xf_clipboard_changed`, triggering a heap use after free. Version 3.23.0 fixes the issue.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00651 51st percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial FreeRDP (FreeRDP): 3.23.0Red Hat: 3 advisoriesRed Hat: 4 fixed, 2 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 3.23.03.23.0Patch availableCNA
  • FreeRDP VendorFreeRDP Affected before 3.23.0 Fixed in 3.23.0 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:*before 3.23.0VulnerableFreeRDP
  • cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:* Versions before 3.23.0 Vulnerable ·FreeRDP

Remediation

  • Fix · CNA FreeRDP (FreeRDP) Fixed in 3.23.0

Red Hat 3 advisories

  • RHSA-2026:20605 Released 2026-05-26 · Red Hat rating Moderate
    freerdp security update
    • Red Hat Enterprise Linux AppStream EUS (v. 10.0) freerdp-2:3.10.3-3.el10_0.7, freerdp-libs-2:3.10.3-3.el10_0.7, libwinpr-2:3.10.3-3.el10_0.7
    • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) freerdp-devel-2:3.10.3-3.el10_0.7, freerdp-server-2:3.10.3-3.el10_0.7, libwinpr-devel-2:3.10.3-3.el10_0.7
  • RHSA-2026:19142 Released 2026-05-19 · Red Hat rating Moderate
    freerdp security update
    • Red Hat Enterprise Linux AppStream (v. 10) freerdp-2:3.10.3-12.el10_2.5, freerdp-libs-2:3.10.3-12.el10_2.5, libwinpr-2:3.10.3-12.el10_2.5
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) freerdp-devel-2:3.10.3-12.el10_2.5, freerdp-server-2:3.10.3-12.el10_2.5, libwinpr-devel-2:3.10.3-12.el10_2.5
  • RHSA-2026:16014 Released 2026-05-11 · Red Hat rating Moderate
    freerdp security update
    • Red Hat Enterprise Linux AppStream (v. 10) freerdp-2:3.10.3-5.el10_1.8, freerdp-libs-2:3.10.3-5.el10_1.8, libwinpr-2:3.10.3-5.el10_1.8
    • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) freerdp-devel-2:3.10.3-5.el10_1.8, freerdp-server-2:3.10.3-5.el10_1.8, libwinpr-devel-2:3.10.3-5.el10_1.8

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix yet
Red Hat Enterprise Linux 8AffectedNo fix planned: Will not fix
Red Hat Enterprise Linux AppStream (v. 10)Fixed RHSA-2026:16014, RHSA-2026:19142
Red Hat Enterprise Linux AppStream EUS (v. 10.0)Fixed RHSA-2026:20605
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10)Fixed RHSA-2026:16014, RHSA-2026:19142
Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0)Fixed RHSA-2026:20605
Not affected: 2 products
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-25997

References

Exploit 1

Patch 8

  • 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