CVE-2026-91953: FreeRDP versions before 3.31.0 contain a heap buffer overflow vulnerability in nego_send_negotiation_request()

Q: How do I fix CVE-2026-91953?

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

Q: Is CVE-2026-91953 being exploited?

CVE-2026-91953 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-2026-91953 affect?

CVE-2026-91953 affects freerdp. Severity is medium (CVSS 6.5). FreeRDP versions before 3.31.0 contain a heap buffer overflow vulnerability in nego_send_negotiation_request() that fails to validate the LB_LOAD_BALANCE_INFO field length before writing to a fixed 512-byte buffer. A malicious RDP server or

Q: How urgent is CVE-2026-91953?

Priority 38/100. Public exploit reference

Routine

MEDIUM 6.5UPGRADE

CVE-2026-91953 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 a heap buffer overflow vulnerability in nego_send_negotiation_request() that fails to validate the LB_LOAD_BALANCE_INFO field length before writing to a fixed 512-byte buffer. A malicious RDP server or man-in-the-middle can send a Server Redirection PDU with an oversized LB_LOAD_BALANCE_INFO value to overflow the buffer with attacker-controlled content, causing denial of service or heap corruption before aut

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	None
User interaction	Required
EPSS exploit chance	0.5% (top 60%)
CISA exploited list	No
Weakness	CWE-120
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.

Advisories and coverage

Official advisories

Amazon Linux 2 ALAS: ALAS2-2026-3938 (important): freerdp 2026-09-28

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-2026-91953?

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

Is CVE-2026-91953 being exploited?

CVE-2026-91953 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-2026-91953 affect?

CVE-2026-91953 affects freerdp. Severity is medium (CVSS 6.5). FreeRDP versions before 3.31.0 contain a heap buffer overflow vulnerability in nego_send_negotiation_request() that fails to validate the LB_LOAD_BALANCE_INFO field length before writing to a fixed 512-byte buffer. A malicious RDP server or

How urgent is CVE-2026-91953?

Priority 38/100. Public exploit reference

Software pages

WinRM and RDP vulnerabilities

Related CVEs

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References

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