CVE-2026-52539

CRITICALPre-NVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

Score 9.1 from GitHub Security Advisory (severity: CRITICAL) published 2026-07-30. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 9.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 3 sources updated this week
9.1EG
EchelonGraph verdictPlan mitigationSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 9.1Exploit: None knownExposed services: Not assessed

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

Outstatic CMS <= 2.1.9 contains a hardcoded JWT signing secret. When the OST_TOKEN_SECRET environment variable is not set, the application falls back to the default value which is publicly visible in the source code repository. An unauthenticated remote attacker can exploit this by forging JWT session tokens with arbitrary user data and full administrative permissions.

CVSS v3
9.1
EG Score
9.1CRITICALmedium confidence
EG Risk
56
EG Risk 56/100CISA SSVC

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
Severity91% × 45%
Exploitation1% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.
EPSS PROB
0.5%
EPSS %ILE
42nd
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

July 30, 2026

Last Modified

July 31, 2026

Advisory Details (2)

Auto-updated Sep 16, 2026
No patch confirmed yet.
generic

outstatic/packages/outstatic/src/utils/constants.ts at canary · avitorio/outstatic · GitHub

https://github.com/avitorio/outstatic/blob/canary/packages/outstatic/src/utils/constants.ts
generic

GitHub - avitorio/outstatic: Outstatic - A Static Site CMS for Markdown. A dashboard to write, edit, and publish Markdown and MDX stored in your GitHub repository. · GitHub

https://github.com/avitorio/outstatic

Vendor Advisories for CVE-2026-52539(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 / 125× 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.

Showing the most recent 100 of 392 total refreshes for this CVE.

  1. 2026-10-05 00:05 UTCEG score recompute
  2. 2026-10-05 00:05 UTCGHSA enrichment
  3. 2026-10-04 23:22 UTCEPSS rescore
  4. 2026-10-04 12:34 UTCGHSA enrichment
  5. 2026-10-04 06:57 UTCEG score recompute
  6. 2026-10-04 06:57 UTCGHSA enrichment
  7. 2026-10-03 14:26 UTCEPSS rescore
  8. 2026-10-03 03:11 UTCGHSA enrichment
  9. 2026-10-02 17:56 UTCEG score recompute
  10. 2026-10-02 17:56 UTCGHSA enrichment
  11. 2026-10-02 17:56 UTCEPSS rescore
  12. 2026-10-01 19:50 UTCEPSS rescore
  13. 2026-10-01 14:36 UTCGHSA enrichment
  14. 2026-10-01 10:58 UTCGHSA enrichment
  15. 2026-10-01 07:08 UTCGHSA enrichment
  16. 2026-10-01 03:31 UTCEG score recompute
  17. 2026-10-01 03:31 UTCGHSA enrichment
  18. 2026-09-30 15:03 UTCEPSS rescore
  19. 2026-09-29 15:22 UTCEPSS rescore
  20. 2026-09-29 07:32 UTCEG score recompute
  21. 2026-09-29 07:32 UTCGHSA enrichment
  22. 2026-09-28 13:51 UTCEPSS rescore
  23. 2026-09-28 10:53 UTCGHSA enrichment
  24. 2026-09-28 07:12 UTCGHSA enrichment
  25. 2026-09-28 03:13 UTCGHSA enrichment
Show 75 more
  1. 2026-09-27 19:34 UTCEG score recompute
  2. 2026-09-27 19:34 UTCGHSA enrichment
  3. 2026-09-27 13:48 UTCEPSS rescore
  4. 2026-09-26 15:59 UTCEPSS rescore
  5. 2026-09-26 00:27 UTCEPSS rescore
  6. 2026-09-25 09:38 UTCGHSA enrichment
  7. 2026-09-25 05:28 UTCEG score recompute
  8. 2026-09-25 05:28 UTCGHSA enrichment
  9. 2026-09-24 09:51 UTCGHSA enrichment
  10. 2026-09-24 06:14 UTCGHSA enrichment
  11. 2026-09-24 01:23 UTCGHSA enrichment
  12. 2026-09-23 21:46 UTCEG score recompute
  13. 2026-09-23 21:46 UTCGHSA enrichment
  14. 2026-09-23 17:53 UTCEPSS rescore
  15. 2026-09-23 08:55 UTCGHSA enrichment
  16. 2026-09-23 05:18 UTCGHSA enrichment
  17. 2026-09-23 01:17 UTCGHSA enrichment
  18. 2026-09-22 21:37 UTCGHSA enrichment
  19. 2026-09-22 15:43 UTCEG score recompute
  20. 2026-09-22 15:43 UTCGHSA enrichment
  21. 2026-09-20 20:16 UTCEPSS rescore
  22. 2026-09-20 11:15 UTCGHSA enrichment
  23. 2026-09-20 03:56 UTCGHSA enrichment
  24. 2026-09-20 00:19 UTCEG score recompute
  25. 2026-09-20 00:19 UTCGHSA enrichment
  26. 2026-09-19 08:17 UTCGHSA enrichment
  27. 2026-09-19 04:41 UTCGHSA enrichment
  28. 2026-09-18 22:27 UTCEG score recompute
  29. 2026-09-18 22:27 UTCGHSA enrichment
  30. 2026-09-18 19:28 UTCEPSS rescore
  31. 2026-09-18 18:50 UTCGHSA enrichment
  32. 2026-09-18 15:12 UTCGHSA enrichment
  33. 2026-09-18 08:59 UTCGHSA enrichment
  34. 2026-09-18 05:15 UTCGHSA enrichment
  35. 2026-09-18 01:38 UTCEG score recompute
  36. 2026-09-18 01:38 UTCGHSA enrichment
  37. 2026-09-17 08:59 UTCGHSA enrichment
  38. 2026-09-17 05:11 UTCGHSA enrichment
  39. 2026-09-17 01:34 UTCEG score recompute
  40. 2026-09-17 01:34 UTCGHSA enrichment
  41. 2026-09-16 14:08 UTCEPSS rescore
  42. 2026-09-16 11:47 UTCGHSA enrichment
  43. 2026-09-16 05:47 UTCEG score recompute
  44. 2026-09-16 05:46 UTCGHSA enrichment
  45. 2026-09-16 05:15 UTCEPSS rescore
  46. 2026-09-15 07:44 UTCEG score recompute
  47. 2026-09-15 07:44 UTCGHSA enrichment
  48. 2026-09-14 15:03 UTCGHSA enrichment
  49. 2026-09-14 10:20 UTCGHSA enrichment
  50. 2026-09-14 06:43 UTCGHSA enrichment
  51. 2026-09-14 03:06 UTCGHSA enrichment
  52. 2026-09-13 23:29 UTCGHSA enrichment
  53. 2026-09-13 19:52 UTCEG score recompute
  54. 2026-09-13 19:52 UTCGHSA enrichment
  55. 2026-09-13 16:47 UTCEPSS rescore
  56. 2026-09-13 15:19 UTCGHSA enrichment
  57. 2026-09-13 11:05 UTCGHSA enrichment
  58. 2026-09-13 07:12 UTCGHSA enrichment
  59. 2026-09-13 03:36 UTCGHSA enrichment
  60. 2026-09-12 23:59 UTCGHSA enrichment
  61. 2026-09-12 19:42 UTCGHSA enrichment
  62. 2026-09-12 16:05 UTCEG score recompute
  63. 2026-09-12 16:05 UTCGHSA enrichment
  64. 2026-09-12 12:28 UTCGHSA enrichment
  65. 2026-09-12 08:31 UTCGHSA enrichment
  66. 2026-09-12 04:18 UTCGHSA enrichment
  67. 2026-09-12 00:38 UTCGHSA enrichment
  68. 2026-09-11 18:43 UTCGHSA enrichment
  69. 2026-09-11 15:06 UTCEG score recompute
  70. 2026-09-11 15:06 UTCGHSA enrichment
  71. 2026-09-11 14:53 UTCEPSS rescore
  72. 2026-09-11 08:45 UTCGHSA enrichment
  73. 2026-09-11 05:08 UTCGHSA enrichment
  74. 2026-09-11 01:23 UTCGHSA enrichment
  75. 2026-09-10 19:48 UTCGHSA enrichment

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Frequently asked(5)

What is CVE-2026-52539?
CVE-2026-52539 is a critical vulnerability published on July 30, 2026. Outstatic CMS <= 2.1.9 contains a hardcoded JWT signing secret. When the OSTTOKENSECRET environment variable is not set, the application falls back to the default value which is publicly visible in the source code repository. An unauthenticated remote attacker can exploit this by forging JWT…
When was CVE-2026-52539 disclosed?
CVE-2026-52539 was first published on July 30, 2026, with the most recent update on July 31, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-52539 actively exploited?
CVE-2026-52539 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (42nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-52539?
CVE-2026-52539 has a CVSS v3.1 base score of 9.1 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-52539?
No fix for CVE-2026-52539 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The vendor advisories EchelonGraph has for CVE-2026-52539 are linked in the Vendor Advisories panel on this page.

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