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 — 3 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
34%
KEV
Not listed

Published

August 28, 2026

Last Modified

September 1, 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 21× in last 7d / 74× 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 06:41 UTCEG score recompute
  2. 2026-09-21 06:41 UTCGHSA enrichment
  3. 2026-09-20 20:16 UTCEPSS rescore
  4. 2026-09-20 08:16 UTCEG score recompute
  5. 2026-09-20 08:16 UTCGHSA enrichment
  6. 2026-09-19 08:04 UTCEG score recompute
  7. 2026-09-19 08:04 UTCGHSA enrichment
  8. 2026-09-18 19:28 UTCEPSS rescore
  9. 2026-09-18 09:40 UTCEG score recompute
  10. 2026-09-18 09:40 UTCGHSA enrichment
  11. 2026-09-17 19:32 UTCEPSS rescore
  12. 2026-09-17 11:16 UTCEG score recompute
  13. 2026-09-17 11:16 UTCGHSA enrichment
  14. 2026-09-16 14:09 UTCEPSS rescore
  15. 2026-09-16 12:51 UTCEG score recompute
  16. 2026-09-16 12:51 UTCGHSA enrichment
  17. 2026-09-16 05:15 UTCEPSS rescore
  18. 2026-09-15 14:27 UTCEG score recompute
  19. 2026-09-15 14:27 UTCGHSA enrichment
  20. 2026-09-15 03:12 UTCEPSS rescore
  21. 2026-09-14 16:02 UTCGHSA enrichment
  22. 2026-09-13 17:38 UTCEG score recompute
  23. 2026-09-13 17:38 UTCGHSA enrichment
  24. 2026-09-13 16:48 UTCEPSS rescore
  25. 2026-09-12 19:13 UTCEG score recompute
Show 49 more
  1. 2026-09-12 19:13 UTCGHSA enrichment
  2. 2026-09-12 15:02 UTCEPSS rescore
  3. 2026-09-11 20:48 UTCEG score recompute
  4. 2026-09-11 20:48 UTCGHSA enrichment
  5. 2026-09-11 14:53 UTCEPSS rescore
  6. 2026-09-11 09:38 UTCEPSS rescore
  7. 2026-09-10 22:18 UTCEG score recompute
  8. 2026-09-10 22:18 UTCGHSA enrichment
  9. 2026-09-10 09:35 UTCEPSS rescore
  10. 2026-09-09 23:54 UTCGHSA enrichment
  11. 2026-09-09 00:30 UTCEG score recompute
  12. 2026-09-09 00:30 UTCGHSA enrichment
  13. 2026-09-08 22:01 UTCEPSS rescore
  14. 2026-09-07 15:02 UTCGHSA enrichment
  15. 2026-09-06 14:14 UTCEG score recompute
  16. 2026-09-06 14:14 UTCGHSA enrichment
  17. 2026-09-06 13:48 UTCEPSS rescore
  18. 2026-09-05 15:49 UTCEG score recompute
  19. 2026-09-05 15:49 UTCGHSA enrichment
  20. 2026-09-05 15:31 UTCEPSS rescore
  21. 2026-09-04 17:23 UTCEG score recompute
  22. 2026-09-04 17:23 UTCGHSA enrichment
  23. 2026-09-04 05:07 UTCEPSS rescore
  24. 2026-09-03 18:57 UTCGHSA enrichment
  25. 2026-09-02 20:25 UTCEG score recompute
  26. 2026-09-02 20:25 UTCGHSA enrichment
  27. 2026-09-02 14:12 UTCEPSS rescore
  28. 2026-09-01 21:02 UTCEG score recompute
  29. 2026-09-01 21:02 UTCGHSA enrichment
  30. 2026-09-01 13:54 UTCEPSS rescore
  31. 2026-09-01 06:12 UTCEG score recompute
  32. 2026-09-01 06:12 UTCGHSA enrichment
  33. 2026-09-01 04:40 UTCEPSS rescore
  34. 2026-08-31 07:46 UTCEG score recompute
  35. 2026-08-31 07:46 UTCGHSA enrichment
  36. 2026-08-30 19:18 UTCEPSS rescore
  37. 2026-08-30 09:22 UTCEG score recompute
  38. 2026-08-30 09:22 UTCGHSA enrichment
  39. 2026-08-30 01:22 UTCEPSS rescore
  40. 2026-08-29 10:53 UTCEG score recompute
  41. 2026-08-29 10:53 UTCGHSA enrichment
  42. 2026-08-28 21:42 UTCEPSS rescore
  43. 2026-08-28 12:24 UTCEG score recompute
  44. 2026-08-28 12:24 UTCGHSA enrichment
  45. 2026-08-28 11:27 UTCEG score recompute
  46. 2026-08-28 11:27 UTCGHSA enrichment
  47. 2026-08-28 08:25 UTCEG score recompute
  48. 2026-08-28 07:33 UTCEG score recompute
  49. 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, with the most recent update on September 1, 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 66.0% 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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