CVE-2026-8034

CRITICALNVD 9.89.8
EchelonGraph scoreMEDIUM confidence

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

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, GitHub Security Advisory, NVD CVSS v3
Trending — 3 sources updated this week

Also known asEUVD-2026-28464 (ENISA EUVD) · GHSA-w548-vv26-rff6 (GitHub Security Advisories)Source: ENISA EUVD

9.8EG
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: 0.5%CVSS: 9.8Exploit: None knownExposed services: Not assessed

The CVE record names the fixed release — apply it.

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
9.8CRITICALmedium confidence
EG Risk
44
EG Risk 44/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity98% × 45%
Impact severity (EG Severity): CVSS 9.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.5% × 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 every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (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
0.5%
EPSS %ILE
44th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.

EG Severity
9.8 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.5% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-29). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

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

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (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)60 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 partial (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

May 7, 2026

Last Modified

October 26, 2026

Advisory Details (5)

Auto-updated Oct 27, 2026
Fix named in the CVE record.
Web page

Release notes - GitHub Enterprise Server 3.20 Docs

https://docs.github.com/en/[email protected]/admin/release-notes#3.20.2
Web page

Release notes - GitHub Enterprise Server 3.19 Docs

https://docs.github.com/en/[email protected]/admin/release-notes#3.19.6
Web page

Release notes - GitHub Enterprise Server 3.18 Docs

https://docs.github.com/en/[email protected]/admin/release-notes#3.18.9
Web page

Release notes - GitHub Enterprise Server 3.17 Docs

https://docs.github.com/en/[email protected]/admin/release-notes#3.17.15
Web page

Release notes - GitHub Enterprise Server 3.16 Docs

https://docs.github.com/en/[email protected]/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 21× in last 7d / 68× 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.

Showing the most recent 96 of 351 refreshes on record for this CVE.

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. 4 repeat rows among the latest 100 are merged into the row they repeat. The 255 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-29 17:30 UTCEG score recompute
  2. 2026-10-29 17:30 UTCGHSA enrichmentGHSA-w548-vv26-rff6 · GitHub severity HIGH · GitHub CVSS 9.8
  3. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  4. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  5. 2026-10-28 15:22 UTCEG score recompute
  6. 2026-10-28 15:22 UTCGHSA enrichmentGHSA-w548-vv26-rff6 · GitHub severity HIGH · GitHub CVSS 9.8
  7. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  8. 2026-10-27 13:14 UTCGHSA enrichmentGHSA-w548-vv26-rff6 · GitHub severity HIGH · GitHub CVSS 9.8
  9. 2026-10-26 20:27 UTCEG score recompute
  10. 2026-10-26 20:27 UTCGHSA enrichmentGHSA-w548-vv26-rff6 · GitHub severity HIGH · GitHub CVSS 9.8
  11. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  12. 2026-10-26 15:10 UTCEG score recompute
  13. 2026-10-26 15:10 UTCGHSA enrichmentGHSA-w548-vv26-rff6 · GitHub severity HIGH · GitHub CVSS 9.8
  14. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  15. 2026-10-25 13:59 UTCEG score recompute
  16. 2026-10-25 12:01 UTCEG score recompute
  17. 2026-10-25 12:00 UTCGHSA enrichmentGHSA-w548-vv26-rff6 · GitHub severity HIGH · GitHub CVSS 9.8
  18. 2026-10-24 16:34 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  19. 2026-10-24 09:50 UTCEG score recompute
  20. 2026-10-24 09:50 UTCGHSA enrichmentGHSA-w548-vv26-rff6 · GitHub severity HIGH · GitHub CVSS 9.8
  21. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  22. 2026-10-23 07:42 UTCEG score recompute
  23. 2026-10-23 07:42 UTCGHSA enrichmentGHSA-w548-vv26-rff6 · GitHub severity HIGH · GitHub CVSS 9.8
  24. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.9% · 58th percentile
  25. 2026-10-22 05:33 UTCEG score recompute
Show 71 more
  1. 2026-10-22 05:32 UTCGHSA enrichmentGHSA-w548-vv26-rff6 · GitHub severity HIGH · GitHub CVSS 9.8
  2. 2026-10-21 16:34 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  3. 2026-10-21 03:23 UTCEG score recompute
  4. 2026-10-21 03:23 UTCGHSA enrichmentGHSA-w548-vv26-rff6 · GitHub severity HIGH · GitHub CVSS 9.8
  5. 2026-10-20 16:34 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  6. 2026-10-20 01:13 UTCEG score recompute
  7. 2026-10-20 01:13 UTCGHSA enrichmentGHSA-w548-vv26-rff6 · GitHub severity HIGH · GitHub CVSS 9.8
  8. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  9. 2026-10-18 22:59 UTCEG score recompute
  10. 2026-10-18 22:59 UTCGHSA enrichmentGHSA-w548-vv26-rff6 · GitHub severity HIGH · GitHub CVSS 9.8
  11. 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  12. 2026-10-18 03:10 UTCEG score recompute
  13. 2026-10-17 20:48 UTCEG score recompute
  14. 2026-10-17 20:48 UTCGHSA enrichmentGHSA-w548-vv26-rff6 · GitHub severity HIGH · GitHub CVSS 9.8
  15. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  16. 2026-10-16 18:39 UTCEG score recompute
  17. 2026-10-16 18:38 UTCGHSA enrichmentGHSA-w548-vv26-rff6 · GitHub severity HIGH · GitHub CVSS 9.8
  18. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  19. 2026-10-15 16:33 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  20. 2026-10-15 15:18 UTCEG score recompute
  21. 2026-10-15 15:18 UTCGHSA enrichmentGHSA-w548-vv26-rff6 · GitHub severity HIGH · GitHub CVSS 9.8
  22. 2026-10-14 16:34 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  23. 2026-10-14 09:45 UTCEG score recompute
  24. 2026-10-14 09:44 UTCGHSA enrichmentGHSA-w548-vv26-rff6 · GitHub severity HIGH · GitHub CVSS 9.8
  25. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  26. 2026-10-13 07:33 UTCEG score recompute
  27. 2026-10-13 07:33 UTCGHSA enrichmentGHSA-w548-vv26-rff6 · GitHub severity HIGH · GitHub CVSS 9.8
  28. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  29. 2026-10-12 14:57 UTCEG score recompute
  30. 2026-10-12 05:23 UTCGHSA enrichmentGHSA-w548-vv26-rff6 · GitHub severity HIGH · GitHub CVSS 9.8
  31. 2026-10-11 19:21 UTCEG score recompute
  32. 2026-10-11 16:37 UTCEG score recompute
  33. 2026-10-11 13:56 UTCEG score recompute
  34. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  35. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  36. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  37. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  38. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  39. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.9% · 57th percentile
  40. 2026-10-05 17:44 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  41. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  42. 2026-10-01 19:51 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  43. 2026-09-30 15:04 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  44. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  45. 2026-09-27 13:49 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  46. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  47. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.9% · 56th percentile
  48. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  49. 2026-09-22 16:01 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  50. 2026-09-21 21:09 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  51. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.5% · 43rd percentile
  52. 2026-09-17 19:32 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  53. 2026-09-16 14:09 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  54. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  55. 2026-09-15 03:12 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  56. 2026-09-13 16:48 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  57. 2026-09-12 15:02 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  58. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  59. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  60. 2026-09-06 13:48 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  61. 2026-09-05 15:31 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  62. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  63. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  64. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  65. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  66. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  67. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  68. 2026-08-28 21:42 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  69. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  70. 2026-08-26 14:47 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  71. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.4% · 30th percentile

Frequently asked(5)

What is CVE-2026-8034?
CVE-2026-8034 is a critical-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-8034 published?
The CVE record for CVE-2026-8034 was published on May 7, 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 October 26, 2026; the record at its source may have been updated since.
Is CVE-2026-8034 actively exploited?
CVE-2026-8034 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (44th percentile of EPSS-scored CVEs).
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?
The CVE record for CVE-2026-8034 names the fix: "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."

Dependency Blast Radius

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