CVE-2026-109255: Heap Overflow (CVSS 6.8)

Description

FreeRDP 3.0.0 before 3.32.0 contains an integer truncation vulnerability in license_check_stream_length that allows a malicious RDP server to trigger a heap buffer overflow on 32-bit clients. Attackers can send a crafted SERVER_LICENSE_REQUEST with a large scopeCount that bypasses length checks, causing out-of-bounds writes leading to denial of service or remote code execution.

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CVSS v3.1 Score

6.8

MEDIUM

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

EPSS — Exploit Prediction

0.0046

Probability of exploitation

0.38%

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-122 CWE-122

References

Other References

https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-hxw3-57rq-3v4m https://www.vulncheck.com/advisories/freerdp-3.0.0-before-3.32.0-heap-buffer-overflow-via-license-check-stream-length https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-hxw3-57rq-3v4m

Frequently Asked Questions

What is CVE-2026-109255? +

FreeRDP 3.0.0 before 3.32.0 contains an integer truncation vulnerability in license_check_stream_length that allows a malicious RDP server to trigger a heap buffer overflow on 32-bit clients. Attackers can send a crafted SERVER_LICENSE_REQUEST with a large scopeCount that bypasses length checks, causing out-of-bounds writes leading to denial of service or remote code execution. It has a CVSS v3.1 base score of 6.8 (MEDIUM).

How severe is CVE-2026-109255? +

CVE-2026-109255 has a CVSS v3.1 score of 6.8 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0046, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-109255? +

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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CVE-2026-109255