CVE-2026-5845Network attack vector

Cross-repository access via revoked installation fallback

Published Apr 21, 2026 · Updated Apr 21, 2026

Improper authorization in GitHub Enterprise Server 3.14.0 through 3.20.0 allows remote authenticated users to access private repositories. Scoped user-to-server token authorization treats a revoked or deleted GitHub App installation as a global installation context instead of rejecting the token. Exploitation requires a scoped token and revocation timing or SSH push attribution, enabling repository reads and potentially writes outside the token's intended scope.

CVSS severity7.2
High
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authorization in GitHub Enterprise Server 3.14.0 through 3.20.0 allows remote authenticated users to access private repositories. Scoped user-to-server token authorization treats a revoked or deleted GitHub App installation as a global installation context instead of rejecting the token. Exploitation requires a scoped token and revocation timing or SSH push attribution, enabling repository reads and potentially writes outside the token's intended scope.

The record

CVE
CVE-2026-5845
Published
Apr 21, 2026
Updated
Apr 21, 2026
Vendor
Twitter
Product
GitHub Enterprise Server
Classifications
CWE-639, CAPEC-233, CAPEC-26, T1528
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=3.14.0 <=3.14.25 changes=[{"at":"3.14.26","status":"unaffected"}]
  2. Affected versionversion=3.15.0 <=3.15.20 changes=[{"at":"3.15.21","status":"unaffected"}]
  3. Affected versionversion=3.16.0 <=3.16.16 changes=[{"at":"3.16.17","status":"unaffected"}]
  4. Affected versionversion=3.17.0 <=3.17.13 changes=[{"at":"3.17.14","status":"unaffected"}]
  5. Affected versionversion=3.18.0 <=3.18.7 changes=[{"at":"3.18.8","status":"unaffected"}]
  6. Affected versionversion=3.19.0 <=3.19.4 changes=[{"at":"3.19.5","status":"unaffected"}]
  7. Affected versionversion=3.20.0 <3.20.1 changes=[{"at":"3.20.1","status":"unaffected"}]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Twitter · GitHub Enterprise Serverversion=3.14.0 <=3.14.25 changes=[{"at":"3.14.26","status":"unaffected"}]; version=3.15.0 <=3.15.20 changes=[{"at":"3.15.21","status":"unaffected"}]; version=3.16.0 <=3.16.16 changes=[{"at":"3.16.17","status":"unaffected"}]; version=3.17.0 <=3.17.13 changes=[{"at":"3.17.14","status":"unaffected"}]; version=3.18.0 <=3.18.7 changes=[{"at":"3.18.8","status":"unaffected"}]; version=3.19.0 <=3.19.4 changes=[{"at":"3.19.5","status":"unaffected"}]; version=3.20.0 <3.20.1 changes=[{"at":"3.20.1","status":"unaffected"}]

Published CVSS scores

9.6NISTCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
7.2GitHubCVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:L/SI:L/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-639Authorization Bypass Through User-Controlled Key
CAPEC-233Privilege Escalation
CAPEC-26Leveraging Race Conditions
T1528Steal Application Access Token

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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