CVE-2026-91955: FreeRDP before 3.31.0 fails to validate client-supplied DesktopWidth and DesktopHeight values during GCC negot

Q: How do I fix CVE-2026-91955?

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

Q: Is CVE-2026-91955 being exploited?

CVE-2026-91955 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-2026-91955 affect?

CVE-2026-91955 affects freerdp. Severity is high (CVSS 7.5). FreeRDP before 3.31.0 fails to validate client-supplied DesktopWidth and DesktopHeight values during GCC negotiation, allowing remote attackers to crash the server. Attackers can send crafted RDP packets with zero or oversized dimensions to

Q: How urgent is CVE-2026-91955?

Priority 48/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

HIGH 7.5REMOTEUPGRADE

CVE-2026-91955 is a high-severity flaw (CVSS 7.5) 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 fails to validate client-supplied DesktopWidth and DesktopHeight values during GCC negotiation, allowing remote attackers to crash the server. Attackers can send crafted RDP packets with zero or oversized dimensions to trigger division-by-zero or assertion failures in multifragment update capability calculations, terminating the server process.

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 53%)
CISA exploited list	No
Weakness	CWE-369
Published	2026-09-15
Last modified	2026-09-24

Publisher (CNA): VulnCheck · Vendor: freerdp

Last updated 2026-09-24 · 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
2026-09-24 12:16 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-2026-91955?

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

Is CVE-2026-91955 being exploited?

CVE-2026-91955 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-2026-91955 affect?

CVE-2026-91955 affects freerdp. Severity is high (CVSS 7.5). FreeRDP before 3.31.0 fails to validate client-supplied DesktopWidth and DesktopHeight values during GCC negotiation, allowing remote attackers to crash the server. Attackers can send crafted RDP packets with zero or oversized dimensions to

How urgent is CVE-2026-91955?

Priority 48/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

WinRM and RDP vulnerabilities

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References

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