CVE & CISA-KEV Catalog

CVE-2026-91953

MEDIUM
6.5
CVSS v3
NVD

Description

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 authentication completes.

How to fix

No published remediation has been found for this vulnerability's affected products yet.

Mitigation guidance may be in the linked vendor advisories in the References section below.

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CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionRequired
ScopeUnchanged

Impact

ConfidentialityNone
IntegrityNone
AvailabilityHigh

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

Exploit Intelligence

EPSS data unavailable for this CVE.

References

Other references2

Related Vulnerabilities

Other CWE-120 (Classic Buffer Overflow) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2014-0195Medium6.8100%-Fix
CVE-2017-7269Critical9.8100%KEV-
CVE-2019-11043High8.7100%KEV + RansomFix
CVE-2011-4862High10.095%-Fix
CVE-2007-5659High7.894%KEVFix
CVE-2022-3786High7.592%-Fix

Common questions

How do I fix CVE-2026-91953?

No published fix for CVE-2026-91953 has been found yet. Check the linked vendor advisories for guidance as it becomes available.

How severe is CVE-2026-91953?

CVE-2026-91953 has a CVSS v3 base score of 6.5, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-09-16.