CVE-2026-91953

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreHIGH confidence

Score 6.5 from GitHub Security Advisory (severity: HIGH) published 2026-09-15. a secondary CVSS source baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: Elevated riskExposed: 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 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 v3
6.5
EG Score
6.5(high)
EG Risk
45(Track)
EG Risk 45/100SSVC: 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
Severity65% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
36%
KEV
Not listed

Published

September 15, 2026

Last Modified

September 24, 2026

Advisory Details (2)

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

FreeRDP before 3.31.0 Heap Buffer Overflow via LB_LOAD_BALANCE_INFO | Advisories | VulnCheck

https://www.vulncheck.com/advisories/freerdp-before-3.31.0-heap-buffer-overflow-via-lb-load-balance-info
github Patch Available🟡 PoC Available

Heap buffer overflow in nego_send_negotiation_request via oversized LB_LOAD_BALANCE_INFO routing token · Advisory · FreeRDP/FreeRDP · GitHub

https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-r9pv-ffph-6gg6

Vendor Advisories for CVE-2026-91953(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 21× in last 7d / 32× 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. 2026-09-25 11:00 UTCEG score recompute
  2. 2026-09-25 11:00 UTCGHSA enrichment
  3. 2026-09-24 14:04 UTCEPSS rescore
  4. 2026-09-24 12:18 UTCGHSA enrichment
  5. 2026-09-24 11:05 UTCEG score recompute
  6. 2026-09-24 11:05 UTCGHSA enrichment
  7. 2026-09-23 17:54 UTCEPSS rescore
  8. 2026-09-23 12:23 UTCEG score recompute
  9. 2026-09-23 12:23 UTCGHSA enrichment
  10. 2026-09-22 16:01 UTCEPSS rescore
  11. 2026-09-22 13:40 UTCEG score recompute
  12. 2026-09-22 13:40 UTCGHSA enrichment
  13. 2026-09-21 21:09 UTCEPSS rescore
  14. 2026-09-21 14:58 UTCEG score recompute
  15. 2026-09-21 14:58 UTCGHSA enrichment
  16. 2026-09-20 20:16 UTCEPSS rescore
  17. 2026-09-20 16:04 UTCGHSA enrichment
  18. 2026-09-19 17:18 UTCEG score recompute
  19. 2026-09-19 17:18 UTCGHSA enrichment
  20. 2026-09-18 19:28 UTCEPSS rescore
  21. 2026-09-18 18:36 UTCGHSA enrichment
  22. 2026-09-17 19:53 UTCEG score recompute
  23. 2026-09-17 19:53 UTCGHSA enrichment
  24. 2026-09-17 19:32 UTCEPSS rescore
  25. 2026-09-16 21:07 UTCGHSA enrichment
Show 7 more
  1. 2026-09-16 16:17 UTCEG score recompute
  2. 2026-09-16 16:17 UTCGHSA enrichment
  3. 2026-09-16 14:09 UTCEPSS rescore
  4. 2026-09-15 17:32 UTCEG score recompute
  5. 2026-09-15 16:18 UTCEG score recompute
  6. 2026-09-15 15:23 UTCEG score recompute
  7. 2026-09-15 15:22 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-91953?
CVE-2026-91953 is a medium vulnerability published on September 15, 2026. FreeRDP versions before 3.31.0 contain a heap buffer overflow vulnerability in negosendnegotiationrequest() that fails to validate the LBLOADBALANCEINFO 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…
When was CVE-2026-91953 disclosed?
CVE-2026-91953 was first published in the National Vulnerability Database on September 15, 2026, with the most recent update on September 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-91953 actively exploited?
CVE-2026-91953 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 63.8% of all scored CVEs.
What is the CVSS score of CVE-2026-91953?
CVE-2026-91953 has a CVSS v3 base score of 6.5 (NVD).
How do I remediate CVE-2026-91953?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-91953, 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

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