CVE-2026-91964

HIGHPre-NVD 8.88.8—
EchelonGraph scoreHIGH confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-09-15. a secondary CVSS source baseline 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
8.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 8.8Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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 v3
8.8
EG Score
8.8(high)
EG Risk
40(Track)
EG Risk 40/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity88% × 45%
Exploitation1% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
45%
KEV
Not listed

Published

September 15, 2026

Last Modified

September 16, 2026

Advisory Details (2)

Auto-updated Sep 15, 2026
🔬 Proof of concept available. Patch available. Sources: github.
generic

FreeRDP 2.0.0 through 3.30.0 Heap Buffer Overflow via RoutingToken | Advisories | VulnCheck

https://www.vulncheck.com/advisories/freerdp-2.0.0-through-3.30.0-heap-buffer-overflow-via-routingtoken
github Patch Available🟡 PoC Available

Heap buffer overflow in `nego_send_negotiation_request` when writing the `RoutingToken` · Advisory · FreeRDP/FreeRDP · GitHub

https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-2vf2-grvj-6g8x

Vendor Advisories for CVE-2026-91964(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 25× in last 7d / 25× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-21 01:17 UTCEG score recompute
  2. 2026-09-21 01:17 UTCGHSA enrichment
  3. 2026-09-20 20:16 UTCEPSS rescore
  4. 2026-09-20 12:15 UTCGHSA enrichment
  5. 2026-09-19 23:13 UTCEG score recompute
  6. 2026-09-19 23:13 UTCGHSA enrichment
  7. 2026-09-19 10:16 UTCGHSA enrichment
  8. 2026-09-18 21:19 UTCEG score recompute
  9. 2026-09-18 21:19 UTCGHSA enrichment
  10. 2026-09-18 19:28 UTCEPSS rescore
  11. 2026-09-18 08:21 UTCEG score recompute
  12. 2026-09-18 08:21 UTCGHSA enrichment
  13. 2026-09-17 19:32 UTCEPSS rescore
  14. 2026-09-17 19:22 UTCGHSA enrichment
  15. 2026-09-17 05:56 UTCGHSA enrichment
  16. 2026-09-16 16:55 UTCEG score recompute
  17. 2026-09-16 16:55 UTCGHSA enrichment
  18. 2026-09-16 15:55 UTCEG score recompute
  19. 2026-09-16 15:55 UTCGHSA enrichment
  20. 2026-09-16 14:09 UTCEPSS rescore
  21. 2026-09-16 04:20 UTCEG score recompute
  22. 2026-09-16 04:20 UTCGHSA enrichment
  23. 2026-09-15 16:32 UTCEG score recompute
  24. 2026-09-15 15:23 UTCEG score recompute
  25. 2026-09-15 15:22 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-91964?
CVE-2026-91964 is a high vulnerability published on September 15, 2026. FreeRDP versions before 3.31.0 contain a heap-based buffer overflow in negosendnegotiation_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…
When was CVE-2026-91964 disclosed?
CVE-2026-91964 was first published in the National Vulnerability Database on September 15, 2026, with the most recent update on September 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-91964 actively exploited?
CVE-2026-91964 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 55.2% of all scored CVEs.
What is the CVSS score of CVE-2026-91964?
CVE-2026-91964 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2026-91964?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-91964, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-91964

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