CVE-2026-77298

HIGHPre-NVD 8.78.7
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This high-severity CVE scores 8.7 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4% (31st percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
8.7EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 8.7Exploit: None knownExposed services: Not assessed

The CVE record names the fixed release — apply it.

SeaweedFS is a distributed storage system for files and blobs. In versions 4.39 and earlier, the S3 API accepts an external OIDC JWT sent directly in the Authorization header and maps it to an IAM role without enforcing that role's trust policy, so a federated user can assume a role they are not permitted to hold. The standard STS AssumeRoleWithWebIdentity path rejects such a token when the role's trust policy does not trust the token's federated provider, but the direct S3 bearer path validates only the token itself and then authenticates as the mapped role and evaluates that role's attached S3 permissions. As a result, a valid OIDC user whose token would be denied the role through STS can obtain the role's S3 access, including object read, write, and delete, by presenting the raw OIDC JWT directly to the S3 API. This issue is fixed in version 4.40

CVSS v3
8.7
EG Score
8.7HIGHmedium confidence
EG Risk
39
EG Risk 39/100

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 (value × EchelonGraph’s weight)
Severity87% × 45%
The EG Score, 8.7 of 10.
Exploitation0.4% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: The CVE record names the fixed release. Apply it within your standard update timelines.
EPSS PROB
0.4%
EPSS %ILE
31st
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

The CVE record names the fixed release. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

August 26, 2026

Last Modified

September 9, 2026

Advisory Details (2)

Auto-updated Aug 26, 2026
Fix named in the CVE record. Sources: github, github_commit.
GitHub commit

commit ac524e140a37 (seaweedfs/seaweedfs)

Fix landed in seaweedfs/seaweedfs commit ac524e140a37 — awaiting tagged release

https://github.com/seaweedfs/seaweedfs/commit/ac524e140a37242b2488be9dfffae918da1d4de1
GitHub advisoryMentions a patch (unverified)

S3 OIDC Bearer authentication bypasses IAM role trust policy · Advisory · seaweedfs/seaweedfs · GitHub

https://github.com/seaweedfs/seaweedfs/security/advisories/GHSA-757h-cm9x-wprg

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 15× in last 7d / 56× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 2 repeat rows among the latest 92 are merged into the row they repeat.

  1. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  2. 2026-10-13 06:58 UTCEG score recompute
  3. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  4. 2026-10-12 15:37 UTCEG score recompute
  5. 2026-10-11 19:23 UTCEG score recompute
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  7. 2026-10-11 13:58 UTCEG score recompute
  8. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  9. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  10. 2026-10-10 06:03 UTCEG score recompute
  11. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  12. 2026-10-09 03:19 UTCEG score recompute
  13. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  14. 2026-10-08 01:45 UTCEG score recompute
  15. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  16. 2026-10-06 19:16 UTCEG score recompute
  17. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  18. 2026-10-06 07:35 UTCEG score recompute
  19. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  20. 2026-10-05 04:37 UTCEG score recompute
  21. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  22. 2026-10-03 17:45 UTCEG score recompute
  23. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  24. 2026-10-02 18:52 UTCEG score recompute
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  1. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  2. 2026-09-30 19:57 UTCEG score recompute
  3. 2026-09-30 06:01 UTCEG score recompute
  4. 2026-09-29 15:24 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  5. 2026-09-29 08:46 UTCEG score recompute
  6. 2026-09-28 21:20 UTCEG score recompute
  7. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  8. 2026-09-27 19:29 UTCEG score recompute
  9. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  10. 2026-09-26 20:31 UTCEG score recompute
  11. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  12. 2026-09-26 00:28 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  13. 2026-09-24 17:06 UTCEG score recompute
  14. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  15. 2026-09-23 18:14 UTCEG score recompute
  16. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  17. 2026-09-22 19:21 UTCEG score recompute
  18. 2026-09-22 16:01 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  19. 2026-09-22 07:54 UTCEG score recompute
  20. 2026-09-21 21:09 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  21. 2026-09-20 21:23 UTCEG score recompute
  22. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  23. 2026-09-19 22:26 UTCEG score recompute
  24. 2026-09-18 23:24 UTCEG score recompute
  25. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  26. 2026-09-18 00:32 UTCEG score recompute
  27. 2026-09-16 14:09 UTCEG score recompute
  28. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  29. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  30. 2026-09-15 03:17 UTCEG score recompute
  31. 2026-09-15 03:12 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  32. 2026-09-13 16:59 UTCEG score recompute
  33. 2026-09-12 18:06 UTCEG score recompute
  34. 2026-09-12 15:02 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  35. 2026-09-11 19:11 UTCEG score recompute
  36. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  37. 2026-09-10 20:07 UTCEG score recompute
  38. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  39. 2026-09-09 00:47 UTCEG score recompute
  40. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  41. 2026-09-07 17:15 UTCEG score recompute
  42. 2026-09-06 18:23 UTCEG score recompute
  43. 2026-09-06 13:48 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  44. 2026-09-05 19:30 UTCEG score recompute
  45. 2026-09-04 20:37 UTCEG score recompute
  46. 2026-09-04 08:56 UTCEG score recompute
  47. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  48. 2026-09-02 22:31 UTCEG score recompute
  49. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  50. 2026-09-01 23:28 UTCEG score recompute
  51. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  52. 2026-09-01 12:02 UTCEG score recompute
  53. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  54. 2026-08-31 01:35 UTCEG score recompute
  55. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  56. 2026-08-30 02:43 UTCEG score recompute
  57. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  58. 2026-08-29 03:51 UTCEG score recompute
  59. 2026-08-28 21:42 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  60. 2026-08-27 17:30 UTCEG score recompute
  61. 2026-08-27 17:07 UTCEG score recompute
  62. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.3% · 21st percentile
  63. 2026-08-26 22:24 UTCEG score recompute
  64. 2026-08-26 22:02 UTCEG score recomputeFirst assessed: 8.7 HIGH
  65. 2026-08-26 22:01 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-77298?
CVE-2026-77298 is a high-severity vulnerability; its CVE record was published on August 26, 2026. SeaweedFS is a distributed storage system for files and blobs. In versions 4.39 and earlier, the S3 API accepts an external OIDC JWT sent directly in the Authorization header and maps it to an IAM role without enforcing that role's trust policy, so a federated user can assume a role they are not…
When was the CVE record for CVE-2026-77298 published?
The CVE record for CVE-2026-77298 was published on August 26, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 9, 2026; the record at its source may have been updated since.
Is CVE-2026-77298 actively exploited?
CVE-2026-77298 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (31st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-77298?
CVE-2026-77298 has a CVSS base score of 8.7 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-77298?
The CVE record for CVE-2026-77298 names the fix: "This issue is fixed in version 4.40".

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