← Vulnerability feed

Vulnerability record · CVE-2026-91964 · published 15 September 2026

CVE-2026-91964: Heap-based buffer overflow vulnerability

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.

8.7 CVSS 4.0 High EPSS 0.60% · top 53.5% CWE-122 · Heap-based buffer overflow Awaiting Analysis
8.7CVSS 4.0 base score
0.60%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
2References
24 Sep 2026Last modified by NVD

Description

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: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:

References

LinkTags
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-2vf2-grvj-6g8x
https://www.vulncheck.com/advisories/freerdp-2.0.0-through-3.30.0-heap-buffer-overflow-via-routingtoken

Track CVE-2026-91964 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.3CVE-2026-94127F5 big-ip access policy manager heap-based buffer overflow vulnerabilityWhen a BIG-IP APM access policy and an OAuth profile are configured on a virtual server, specific malicious traffic can lead to remote code execution…KEVEPSS 2.2%9.8CVE-2025-25249Fortinet FortiOS and FortiSwitchManager heap buffer overflow via crafted packetsA heap-based buffer overflow (CWE-122/CWE-787) in Fortinet FortiOS 6.4 through 7.6.3 and FortiSwitchManager 7.0 through 7.2.6 lets an unauthenticated…KEVEPSS 3.9%analysed7.8CVE-2026-85880Windows ALPC heap buffer overflow allows local privilege escalationA heap-based buffer overflow in the Windows ALPC subsystem, combined with use of an uninitialized resource, lets an attacker with existing local acce…KEVEPSS 3.6%analysed7.8CVE-2026-53362Linux kernel IPv6 UDP paged allocation out-of-bounds write__ip6_append_data() in the Linux kernel mis-accounts fraggap on the paged-allocation path, leaving the linear skb area undersized while pagedlen is o…KEVEPSS 0.71%analysed7.8CVE-2026-56155Microsoft AD FS access control flaw allows local privilege elevationActive Directory Federation Services (AD FS) on multiple Windows client and server versions has insufficient granularity in its access control, letti…KEVEPSS 0.35%analysed8.8CVE-2009-3459Adobe Reader and Acrobat heap buffer overflow via crafted PDFAdobe Reader and Acrobat 7.x before 7.1.4, 8.x before 8.1.7, and 9.x before 9.2 contain a heap-based buffer overflow (CWE-122) triggered by a crafted…KEVEPSS 87%analysed7.8CVE-2026-33825Microsoft Defender Antimalware Platform access control flaw allows local privilege escalationMicrosoft Defender Antimalware Platform has insufficient granularity of access control (CWE-1220), letting an authorized local attacker elevate privi…KEVEPSS 0.40%analysed9.8CVE-2025-31201Apple OS Pointer Authentication bypass via arbitrary read/writeApple removed vulnerable code that allowed an attacker holding arbitrary read and write capability to bypass Pointer Authentication across iOS, iPadO…KEVEPSS 14%analysed

Source: NIST National Vulnerability Database (record CVE-2026-91964), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.