Is CVE-2026-8034 in the CISA KEV catalog?

No. CVE-2026-8034 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-8034?

CVE-2026-8034 has a CVSS v3 base score of 9.8 (CRITICAL).

What is the EPSS score for CVE-2026-8034?

CVE-2026-8034 has an EPSS score of 0.38% (30th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-8034?

Upgrade enterprise server to 3.20.2 or later.

CVE & CISA-KEV Catalog

CVE-2026-8034

CRITICAL

9.8

CVSS v3

NVD

Description

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.

CWE-436 CWE-918Server-Side Request Forgery (SSRF)

How to fix

Remediation Available

enterprise serverNVD

Affected:>= 3.20.0, < 3.20.2Fixed in:3.20.2CVE-2026-8034derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

0.38%probability of exploitation in 30 days

30thpercentile

Low risk: more likely to be exploited than 30% of all known CVEs.

References

Vendor Advisory5

Related Vulnerabilities

Other CWE-436 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2025-25292	Critical	9.8	64%	-	Fix
CVE-2022-37436	Medium	5.3	58%	-	Fix
CVE-2021-28474	High	8.8	51%	-	Fix
CVE-2025-25291	Critical	9.8	20%	-	Fix
CVE-2026-63030	Critical	9.8	8.9%	KEV	Fix
CVE-2019-17596	High	7.5	4.7%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-11.