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NVD / CVE Program· CNA GitHub_P

CVE-2026-4296: Incorrect Regular Expression vulnerability in GitHub Enterprise Server allowed unauthorized access to user accounts via OAuth callback URL validation bypass

Noroxi assessment

Priority: Monitor (action score 30/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.42% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No special conditions are required; it is repeatable.
  • Fixed version: GitHub Enterprise Server 3.14.26, 3.15.21, 3.16.17.

Low priority for now. Upgrade to GitHub Enterprise Server 3.14.26, 3.15.21, 3.16.17 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

An incorrect regular expression vulnerability was identified in GitHub Enterprise Server that allowed an attacker to bypass OAuth redirect URI validation. An attacker with knowledge of a first-party OAuth application's registered callback URL could craft a malicious authorization link that, when clicked by a victim, would redirect the OAuth authorization code to an attacker-controlled domain. This could allow the attacker to gain unauthorized access to the victim's account with the scopes granted to the OAuth application. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.20.1, 3.19.5, 3.18.8, 3.17.14, 3.16.17, 3.15.21, 3.14.26. This vulnerability was reported via the GitHub Bug Bounty program.

HighCVSS 7.5 · v4.0—No exploit Fix available
Published
Apr 21, 2026
Updated
Oct 26, 2026
EPSS
0.4% · 36th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_P
7.5
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-4296

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
githubenterprise server

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • github enterprise serverbefore 3.14.26
  • github enterprise server3.15.0 and later · before 3.15.21
  • github enterprise server3.16.0 and later · before 3.16.17
  • github enterprise server3.17.0 and later · before 3.17.14
  • github enterprise server3.18.0 and later · before 3.18.8
  • github enterprise server3.19.0 and later · before 3.19.5
  • github enterprise server3.20.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_P). Independent of NVD's CPE analysis and usually ahead of it.

  • GitHub Enterprise Server

    • 3.14.0 and later · up to and including 3.14.25affected · semverfixed in 3.14.26
    • 3.15.0 and later · up to and including 3.15.20affected · semverfixed in 3.15.21
    • 3.16.0 and later · up to and including 3.16.16affected · semverfixed in 3.16.17
    • 3.17.0 and later · up to and including 3.17.13affected · semverfixed in 3.17.14
    • 3.18.0 and later · up to and including 3.18.7affected · semverfixed in 3.18.8
    • 3.19.0 and later · up to and including 3.19.4affected · semverfixed in 3.19.5
    • 3.20.0 and later · before 3.20.1affected · semverfixed in 3.20.1

Same product

github: all records

Other highest-scoring records for the same primary product.

  • CVE-2024-0200Unsafe Reflection in Github Enterprise Server leading to Command Injection
    61This week
  • CVE-2024-0507Privilege Escalation by Code Injection in the Management Console in GitHub Enterprise Server
    55Plan
  • CVE-2026-3854Remote code execution via git push option injection in GitHub Enterprise Server
    46Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-3582Mar 10, 2026 · Incorrect Authorization in GitHub Enterprise Server allows access to issue and commit search results without repo scope
    21Monitor
  • ← EarlierCVE-2026-3307Apr 21, 2026 · Authorization bypass in GitHub Enterprise Server secret scanning push protection allows cross-repository modification of delegated bypass reviewers
    21Monitor
  • Later →CVE-2026-5512Apr 21, 2026 · Improper authorization vulnerability in GitHub Enterprise Server allowed disclosure of private repository names via mobile upload policy API
    21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
GitHub Enterprise Server3.14.26Vendor (CNA)
GitHub Enterprise Server3.15.21Vendor (CNA)
GitHub Enterprise Server3.16.17Vendor (CNA)
GitHub Enterprise Server3.17.14Vendor (CNA)
GitHub Enterprise Server3.18.8Vendor (CNA)
GitHub Enterprise Server3.19.5Vendor (CNA)
GitHub Enterprise Server3.20.1Vendor (CNA)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
P
Scope
X

Weakness class (CWE)

CWE-185 · Incorrect Regular Expression

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records