CVE-2026-40254

Description

FreeRDP is a free implementation of the Remote Desktop Protocol. Versions prior to 3.25.0 have an off-by-one in the path traversal filter in `channels/drive/client/drive_file.c`. The `contains_dotdot()` function catches `../` and `..\` mid-path but misses `..` when it's the last component with no trailing separator. A rogue RDP server can read, list, or write files one directory above the client's shared folder through RDPDR requests. This requires the victim to connect with drive redirection enabled. Version 3.25.0 patches the issue.

CVSS v3.1 Score

4.2

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N

EPSS — Exploit Prediction

0.0005

Probability of exploitation

0.16%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-193 CWE-193

Affected Products

Vendor	Product	Versions
freerdp	freerdp	< 3.25.0

References

Advisories & Patches

https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-3xpj-m4hx-8vmx https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-3xpj-m4hx-8vmx

Exploits

https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-3xpj-m4hx-8vmx https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-3xpj-m4hx-8vmx

Frequently Asked Questions

What is CVE-2026-40254? +

FreeRDP is a free implementation of the Remote Desktop Protocol. Versions prior to 3.25.0 have an off-by-one in the path traversal filter in `channels/drive/client/drive_file.c`. The `contains_dotdot()` function catches `../` and `..\` mid-path but misses `..` when it's the last component with no trailing separator. A rogue RDP server can read, list, or write files one directory above the client's shared folder through RDPDR requests. This requires the victim to connect with drive redirection enabled. Version 3.25.0 patches the issue. It has a CVSS v3.1 base score of 4.2 (MEDIUM).

How severe is CVE-2026-40254? +

CVE-2026-40254 has a CVSS v3.1 score of 4.2 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0005, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-40254? +

CVE-2026-40254 affects products from freerdp, specifically: freerdp. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-40254? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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