CVE-2026-8034

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: HIGH) published 2026-05-08. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 9.8Exploit: NoneExposed: 0

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

A server-side request forgery (SSRF) vulnerability was identified in the GitHub Enterprise Server notebook viewer that allowed an attacker to access internal services by exploiting URL parser confusion between the validation layer and the HTTP request library. The hostname validation used a different URL parser than the request library, enabling a crafted URL to pass validation while directing the request to an unintended host. Exploitation required network access to the GitHub Enterprise Server instance. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.16.18, 3.17.15, 3.18.9, 3.19.6, and 3.20.2. This vulnerability was reported via the GitHub Bug Bounty program.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
—
EPSS
30.2%
KEV
Not listed

Published

May 7, 2026

Last Modified

May 11, 2026

Advisory Details (5)

Auto-updated May 12, 2026
No patch confirmed yet.
generic

Release notes - GitHub Enterprise Server 3.20 Docs

https://docs.github.com/en/enterprise-server@3.20/admin/release-notes#3.20.2
generic

Release notes - GitHub Enterprise Server 3.19 Docs

https://docs.github.com/en/enterprise-server@3.19/admin/release-notes#3.19.6
generic

Release notes - GitHub Enterprise Server 3.18 Docs

https://docs.github.com/en/enterprise-server@3.18/admin/release-notes#3.18.9
generic

Release notes - GitHub Enterprise Server 3.17 Docs

https://docs.github.com/en/enterprise-server@3.17/admin/release-notes#3.17.15
generic

Release notes - GitHub Enterprise Server 3.16 Docs

https://docs.github.com/en/enterprise-server@3.16/admin/release-notes#3.16.18

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 38× 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 153 total refreshes for this CVE.

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

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Frequently asked(5)

What is CVE-2026-8034?
CVE-2026-8034 is a critical vulnerability published on May 7, 2026. A server-side request forgery (SSRF) vulnerability was identified in the GitHub Enterprise Server notebook viewer that allowed an attacker to access internal services by exploiting URL parser confusion between the validation layer and the HTTP request library. The hostname validation used a…
When was CVE-2026-8034 disclosed?
CVE-2026-8034 was first published in the National Vulnerability Database on May 7, 2026, with the most recent update on May 11, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-8034 actively exploited?
CVE-2026-8034 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 30.2% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-8034?
CVE-2026-8034 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-8034?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-8034, 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.

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