Name: CVE-2026-91964: Heap-based Buffer Overflow
Creator: Rapid7
Published: 2026-09-15T00:00:00.000Z
License: https://www.rapid7.com/legal/website-terms-of-use/
Keywords: CVE, CVE-2026-91964, CWE-122, CVSS 8.8, EPSS 0.00564

FreeRDP versions before 3.31.0 contain a heap-based buffer overflow in nego_send_negotiation_request when processing Server Redirection PDU messages with attacker-controlled LoadBalanceInfo fields. A malicious RDP server can trigger the overflow by sending an arbitrary-length field that gets written to a fixed 512-byte buffer without validation, causing client crashes or potential code execution when chained with memory disclosure.

CVSS Details

CVSS 4.0 Base Score: 8.7 (HIGH)
CVSS 4.0 Vector: (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X)
CVSS 3.1 Base Score: 8.8
CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H)

Covered by Rapid7

Product	Vendor Advisory	Solution File	Added	Published
Alma_linux	—	Upgrade libwinprUpgrade freerdpUpgrade freerdp-develUpgrade libwinpr-develUpgrade freerdp-libs	Oct 11, 2026	Oct 6, 2026
Amazon Linux Ami 2	—	Upgrade freerdpUpgrade libwinpr-develUpgrade freerdp-debuginfoUpgrade freerdp-develUpgrade libwinprUpgrade freerdp-libs	Oct 19, 2026	Oct 19, 2026
Amazon_linux_2023	—	Upgrade freerdp-libs-debuginfoUpgrade freerdp-server-debuginfoUpgrade libwinpr-debuginfoUpgrade freerdp-libsUpgrade freerdp-serverUpgrade libwinprUpgrade freerdp-develUpgrade freerdp-debugsourceUpgrade freerdpUpgrade libwinpr-develUpgrade freerdp-debuginfo	Sep 30, 2026	Sep 15, 2026
Oracle_linux	—	Upgrade freerdp-develUpgrade freerdp-libsUpgrade freerdp-serverUpgrade libwinpr-develUpgrade freerdpUpgrade libwinpr	Oct 22, 2026	Sep 15, 2026
Redhat_linux	—	Upgrade freerdp-serverNo solution existsUpgrade libwinpr-develUpgrade freerdp-libs-debuginfoUpgrade freerdp-libsUpgrade freerdp-debuginfoUpgrade freerdp-debugsourceUpgrade libwinpr-debuginfoUpgrade freerdp-server-debuginfoUpgrade libwinprUpgrade freerdp-develUpgrade freerdp	Sep 17, 2026	Sep 15, 2026
Rocky_linux	—	Upgrade freerdp-debugsourceUpgrade freerdpUpgrade libwinpr-develUpgrade freerdp-debuginfoUpgrade libwinpr-debuginfoUpgrade freerdp-libsUpgrade freerdp-develUpgrade libwinprUpgrade freerdp-serverUpgrade freerdp-server-debuginfoUpgrade freerdp-libs-debuginfo	Oct 8, 2026	Oct 7, 2026
Ubuntu	—	Upgrade freerdp3	Sep 22, 2026	Sep 16, 2026

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