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Vulnerabilities/CVE-2026-4296Public Intelligence Dossier
Source: github · Limited verification•Last verified: •Collection Degraded
CVE-2026-4296Unknown / EvaluatingHIGH (raw)CVSS 8.8CWE-185

An incorrect regular expression vulnerability was identified in GitHub Enterprise Server that allowed an attacker to bypass OAuth redirect URI validation

Published: 22 Apr 2026•Last updated: 27 Oct 2026, 03:40 AM IST•Source identifier: product-cna@github.com
Dossier completeness: source-provided sections 2 / 3 · rule guidance available. Missing source facts count as incomplete.
Official source
CISA KEV catalog
Unknown
KEV status was not determined.
CVSS score
8.8HIGH (raw)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Metric sourcenvd@nist.gov
EPSS probability
0.4%0.004
Percentile37th
Weakness type
CWE-185
No further CWE recorded
Remediation
Patch status unknown
No fixed version or KB recorded

Why It Matters

Analysis dossier

Why It Matters

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.

SOC priority

High

Actively exploited (source statement)

Unknown

Publicly disclosed

Unknown

Risk basis: SOC ecosystem technology relevance; HIGH severity; Source severity; no confirmed exploitation signal

Affected Products & Remediation

1 source-backed product
Affected products and versions (source)
  • github enterprise server · < 3.14.26; >= 3.15.0 < 3.15.21; >= 3.16.0 < 3.16.17; >= 3.17.0 < 3.17.14; >= 3.18.0 < 3.18.8; >= 3.19.0 < 3.19.5; 3.20.0 · NVD CPE · Source
Recorded patch / KBNot provided by source

Vendor or catalog guidance (source)

Not provided by source

Known exploitation (source facts)

Only what a source states. Unknown means no source has said either way; it is not "not exploited".

CISA KEV
Unknown
Exploited (source statement)
Unknown
Publicly disclosed (source)
Unknown

Suggested hunting (rule-based inference)

SecOps Signal recommendation (rule-based inference). These steps are hunting hypotheses from the vulnerability class; they do not state or imply that exploitation occurred here or anywhere.

Matched user-interaction-client (CVSS AV:N, CVSS UI:R)

Exposure

  1. Identify endpoints reporting this CVE, especially those used for email and web browsing.Telemetry: DeviceTvmSoftwareVulnerabilities · A network vector that needs user interaction points at user-facing client software. · Rule user-interaction-client

Exploitation evidence

  1. Review unusual child processes started by the affected client application on affected endpoints.Telemetry: DeviceProcessEvents · Hunting hypothesis from the CVSS vector; it does not show that exploitation occurred. · Rule user-interaction-client

Response

  1. Confirm the source-stated update on affected endpoints.Telemetry: DeviceTvmSoftwareVulnerabilities · A follow-up inventory check verifies remediation. · Rule user-interaction-client

CISA KEV Record

CISA KEV status was not determined for this record.

Change History & Source Data

— No recorded material change

CNA / source
product-cna@github.com
Record status · verification
UPDATED · NVD API
CPE
cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*, cpe:2.3:a:github:enterprise_server:3.20.0:*:*:*:*:*:*:*

Evidence & Provenance

3 public sources
docs.github.comSource recordnvd.nist.govSource recorddocs.github.comSource record

Linked by the query's stored exact CVE association. Review required tables and validation status before use.

Detection Hunting Query
Target: DeviceTvmSoftwareVulnerabilities•Defender XDR
Detect endpoints exposed to CVE-2026-4296
Purpose: Exposure assessment (Category: Exposure Check)Why linked: Query metadata names CVE-2026-4296
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2026-4296"| project DeviceId, DeviceName, OSPlatform, OSVersion, SoftwareVendor, SoftwareName, SoftwareVersion, CveId, VulnerabilitySeverityLevel, RecommendedSecurityUpdate, RecommendedSecurityUpdateId| sort by VulnerabilitySeverityLevel desc
Schema Checked · Not runtime validatedSource: SecOps Signal deterministic template · Limited verificationStatic screening: Passed structure and schema checks; tenant execution is not verified.
Open KQL Library

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Correlated briefings

SecOps Signal surfaces public advisory facts only. A missing value means the source has not published it, not that your environment is unaffected. No tenant inventory is connected.