Medium severity · published Sep 15, 2026
CVE-2026-91953
FreeRDP before 3.31.0 Heap Buffer Overflow via LB_LOAD_BALANCE_INFO
6.5
CVSS
0.5%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 41% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FR
FreeRDP · FreeRDP
before 3.31.0 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-91953
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-91953
Exploit
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-r9pv-ffph-6gg6
Third Party Advisory
https://www.vulncheck.com/advisories/freerdp-before-3.31.0-heap-buffer-overflow-via-lb-load-balance-info
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