CVE-2026-9491

MEDIUMPre-NVD 4.34.3—
EchelonGraph scoreHIGH confidence

Score 4.3 from GitHub Security Advisory published 2026-08-28. a secondary CVSS source baseline 4.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
4.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 4.3Exploit: None knownExposed: 0

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

A server-ide request forgery (SSRF) vulnerability in webhook in Synology Chat Server before 2.4.5-22148 allows remote authenticated users to obtain non-sensitive information.

CVSS v3
4.3
EG Score
4.3(high)
EG Risk
20(Track)
EG Risk 20/100SSVC: 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
Severity43% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
33%
KEV
Not listed

Published

August 28, 2026

Last Modified

August 28, 2026

Advisory Details (1)

Auto-updated Aug 28, 2026
No patch confirmed yet.
generic

Synology_SA_26_10 | Synology Inc.

https://www.synology.com/en-global/security/advisory/Synology_SA_26_10

Vendor Advisories for CVE-2026-9491(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 11× in last 7d / 11× 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. 2026-08-30 01:22 UTCEPSS rescore
  2. 2026-08-29 10:53 UTCEG score recompute
  3. 2026-08-29 10:53 UTCGHSA enrichment
  4. 2026-08-28 21:42 UTCEPSS rescore
  5. 2026-08-28 12:24 UTCEG score recompute
  6. 2026-08-28 12:24 UTCGHSA enrichment
  7. 2026-08-28 11:27 UTCEG score recompute
  8. 2026-08-28 11:27 UTCGHSA enrichment
  9. 2026-08-28 08:25 UTCEG score recompute
  10. 2026-08-28 07:33 UTCEG score recompute
  11. 2026-08-28 07:32 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-9491?
CVE-2026-9491 is a medium vulnerability published on August 28, 2026. A server-ide request forgery (SSRF) vulnerability in webhook in Synology Chat Server before 2.4.5-22148 allows remote authenticated users to obtain non-sensitive information.
When was CVE-2026-9491 disclosed?
CVE-2026-9491 was first published in the National Vulnerability Database on August 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-9491 actively exploited?
CVE-2026-9491 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 67.0% of all scored CVEs.
What is the CVSS score of CVE-2026-9491?
CVE-2026-9491 has a CVSS v3 base score of 4.3 (NVD).
How do I remediate CVE-2026-9491?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-9491, 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-2026-9491

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