Security readout for executives and security teams
Plain-English summary
CVE-2026-25953 affects FreeRDP clients before 3.23.0. A timing bug can make the X11 client read window data after it has been freed. The published impact is limited availability impact, not data theft or full compromise. Organizations using FreeRDP for remote desktop access should plan an update, especially on Linux/X11 endpoints.
Executive priority
Treat as a scheduled security update, not an emergency, unless FreeRDP is heavily used on critical Linux remote-access workstations. The main documented risk is client crash or availability disruption. Patch through normal endpoint or package-management processes.
Technical view
This is a CWE-416 heap-use-after-free in FreeRDP’s X11 RemoteApp/RAIL window handling. The RDPGFX DVC thread obtains an unprotected xfAppWindow pointer through xf_rail_get_window while the main thread can delete that window via a fastpath window-delete order. FreeRDP fixed the issue in version 3.23.0.
Likely exposure
Exposure is likely limited to systems running FreeRDP before 3.23.0, particularly X11 client builds using RemoteApp/RAIL and graphics update paths. The source bundle names FreeRDP as the affected product and does not identify downstream package versions or other products.
Exploitation context
The CVSS vector indicates network attackability, low complexity, no privileges, and no user interaction, with low availability impact. The source bundle does not report active exploitation, and KEV status is false. No public exploit status is established by the provided sources.
Researcher notes
The advisory and commit identify a race/lifetime issue around xf_AppUpdateWindowFromSurface and xf_rail_get_window. The fix should be reviewed for lifetime protection of xfAppWindow across RDPGFX and main-thread window deletion. Provided evidence does not support claims of code execution or exploitation in the wild.
Mitigation direction
- Upgrade FreeRDP to version 3.23.0 or later.
- Prioritize Linux/X11 FreeRDP clients used for remote desktop workflows.
- Check OS vendor advisories for packaged FreeRDP update availability.
- If immediate upgrade is unavailable, review vendor guidance for supported workarounds.
Validation and detection
- Inventory FreeRDP installations and record installed versions.
- Confirm vulnerable systems are older than FreeRDP 3.23.0.
- Identify clients using X11 and RemoteApp/RAIL functionality.
- Verify patched hosts run FreeRDP 3.23.0 or later.
- Monitor vendor advisories for downstream package backports.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-416: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2026-25953 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.5 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P——Primary CVE scoreVulnerability scoring details
Base CVSS 4.0 score
5.5MediumVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-p6rq-rxpc-rh3pCVE reference · x_refsource_CONFIRM
- https://github.com/FreeRDP/FreeRDP/commit/1994e9844212a6dfe0ff12309fef520e888986b5CVE reference · x_refsource_MISC
- https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_rail.c#L257-L290CVE reference · x_refsource_MISC
- https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_window.c#L1462-L1470CVE reference · x_refsource_MISC
- https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/libfreerdp/gdi/gfx.c#L278-L279CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Use After Free
Use After Free represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.