CVE-2026-91961: FreeRDP before 3.31.0 contains a denial-of-service vulnerability in the URBDRC control-transfer request path t

Q: How do I fix CVE-2026-91961?

freerdp: upgrade to 3.31.0. Exact commands for each OS are on this page.

Q: Is CVE-2026-91961 being exploited?

CVE-2026-91961 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-91961 affect?

CVE-2026-91961 affects freerdp. Severity is medium (CVSS 6.5). FreeRDP before 3.31.0 contains a denial-of-service vulnerability in the URBDRC control-transfer request path that fails to validate OutputBufferSize before forwarding to the libusb backend. A malicious RDP server can send a control-transfer

Q: How urgent is CVE-2026-91961?

Priority 30/100. No elevated risk signals yet.

Routine

MEDIUM 6.5UPGRADE

CVE-2026-91961 is a medium-severity flaw (CVSS 6.5) affecting freerdp. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

FreeRDP before 3.31.0 contains a denial-of-service vulnerability in the URBDRC control-transfer request path that fails to validate OutputBufferSize before forwarding to the libusb backend. A malicious RDP server can send a control-transfer request with OutputBufferSize set to 65536, triggering a reachable assertion that terminates the client process.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.4% (top 69%)
CISA exploited list	No
Weakness	CWE-617
Published	2026-09-15
Last modified	2026-09-23

Publisher (CNA): VulnCheck · Vendor: freerdp

Last updated 2026-09-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-09-15 16:17 UTCPublished CVE record published
2026-09-23 20:02 UTCUpdated Record last modified

freerdp freerdp UPGRADE

Affected: < 3.31.0

Fixed in: 3.31.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy freerdp || rpm -q freerdp || freerdp --version

2. UPGRADE to 3.31.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade freerdp

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade freerdp

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-91961?

freerdp: upgrade to 3.31.0. Exact commands for each OS are on this page.

Is CVE-2026-91961 being exploited?

CVE-2026-91961 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-91961 affect?

CVE-2026-91961 affects freerdp. Severity is medium (CVSS 6.5). FreeRDP before 3.31.0 contains a denial-of-service vulnerability in the URBDRC control-transfer request path that fails to validate OutputBufferSize before forwarding to the libusb backend. A malicious RDP server can send a control-transfer

How urgent is CVE-2026-91961?

Priority 30/100. No elevated risk signals yet.

Software pages

WinRM and RDP vulnerabilities

Related CVEs

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References

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