CVE-2026-91945: FreeRDP versions before 3.31.0 contain an out-of-bounds read vulnerability in smartcard response decoders that

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MEDIUM 6.5UPGRADE

CVE-2026-91945 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 versions before 3.31.0 contain an out-of-bounds read vulnerability in smartcard response decoders that fail to validate ATR length fields against fixed inline arrays. Authenticated RDP clients can send oversized ATR lengths in PAKID_CORE_DEVICE_IOCOMPLETION responses to trigger reads past stack or heap objects, causing process termination.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.6% (top 53%)
CISA exploited list	No
Weakness	CWE-125
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 12:13 UTCUpdated Record last modified

freerdp freerdp UPGRADE

Affected: >= 3.28.0 and < 3.31.0

Fixed in: 3.31.0

Safe to downgrade to: a release before 3.28.0

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.

3. If no update is available yet, DOWNGRADE to a release before 3.28.0 (Debian / Ubuntu)

apt-cache madison freerdp sudo apt install freerdp=<VERSION_BEFORE_3.28.0> sudo apt-mark hold freerdp

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list freerdp sudo dnf downgrade freerdp-<VERSION_BEFORE_3.28.0> sudo dnf versionlock add freerdp

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2026-91945?

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

Is CVE-2026-91945 being exploited?

CVE-2026-91945 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-2026-91945 affect?

CVE-2026-91945 affects freerdp. Severity is medium (CVSS 6.5). FreeRDP versions before 3.31.0 contain an out-of-bounds read vulnerability in smartcard response decoders that fail to validate ATR length fields against fixed inline arrays. Authenticated RDP clients can send oversized ATR lengths in PAKID

How urgent is CVE-2026-91945?

Priority 40/100. Public exploit reference

Software pages

WinRM and RDP vulnerabilities

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References

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