CVE-2026-91964: FreeRDP 2.0.0 through 3.30.0 Heap Buffer Overflow via RoutingToken
Vulnerability summary
CVE-2026-91964 is a high (CVSS 8.8) Heap-based Buffer Overflow vulnerability in freerdp. EPSS estimates a 0.56% chance of exploitation in the next 30 days, higher than 46.9% of scored vulnerabilities. 1 public exploit is recorded.
Public exploit (GitHub, Date unknown)
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 3Timeline
- 15-09-2026PublishedVulnerability first disclosed.
- 16-09-2026Last modifiedVulnerability information updated.
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 metrics
7 scores · 4 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- OSV · DebianEcosystem advisory · calculated8.7HighCVSS: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
- NVDNIST8.7HighCVSS: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
- OSV · UbuntuEcosystem advisory · calculated8.8HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- NVDNIST8.8HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.56%
Chance of exploitation in the next 30 days
Percentile
47%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.56% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
1 foundFreerdp
Maturity: poc
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu3 products
- freerdpAll versions (No fix recorded)
- freerdp2All versions (No fix recorded)
- freerdp3< 3.31.0+dfsg-0ubuntu0.24.04.1 | < 3.31.0+dfsg-0ubuntu0.26.04.1
Debian2 products
- freerdp2All versions (No fix recorded)
- freerdp3All versions (No fix recorded) | < 3.31.0+dfsg-1
Freerdp1 product
- freerdp≥ 2.0.0, < 3.0.0 | ≥ 3.0.0, < 3.31.0 | < 3.31.0
3 vendors · 6 products
