CVE-2026-8106Network attack vector

Administrator credential theft via unsanitized redirect attribute

Published May 7, 2026 · Updated May 7, 2026

HTML injection in affected GitHub Enterprise Server releases allows remote attackers to steal administrator credentials through a crafted login link. The /setup/unlock login template places the redirect_to query parameter into an HTML attribute without sanitization, enabling an injected form to collect submitted credentials. Affected versions are 3.19.1 through 3.19.5 and 3.20.0 through 3.20.1; exploitation requires an administrator to open the link and enter credentials.

CVSS severity6.1
Medium
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

HTML injection in affected GitHub Enterprise Server releases allows remote attackers to steal administrator credentials through a crafted login link. The /setup/unlock login template places the redirect_to query parameter into an HTML attribute without sanitization, enabling an injected form to collect submitted credentials. Affected versions are 3.19.1 through 3.19.5 and 3.20.0 through 3.20.1; exploitation requires an administrator to open the link and enter credentials.

The record

CVE
CVE-2026-8106
Published
May 7, 2026
Updated
May 7, 2026
Vendor
Twitter
Product
GitHub Enterprise Server
Classifications
CWE-79, CAPEC-243, T1566.002, T1056.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 7, 2026CVE publishedPublication date reported by the CVE source.
  2. May 7, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=3.19.1 <=3.19.5 changes=[{"at":"3.19.6","status":"unaffected"}]
  2. Affected versionversion=3.20.0 <=3.20.1 changes=[{"at":"3.20.2","status":"unaffected"}]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Twitter · GitHub Enterprise Serverversion=3.19.1 <=3.19.5 changes=[{"at":"3.19.6","status":"unaffected"}]; version=3.20.0 <=3.20.1 changes=[{"at":"3.20.2","status":"unaffected"}]

Published CVSS scores

5.9GitHubCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A: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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CAPEC-243XSS Targeting HTML Attributes
T1566.002Phishing: Spearphishing Link
T1056.003Input Capture: Web Portal Capture

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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