CVE-2026-42849Network attack vector

Account takeover via unsanitized AutosubmitStage input

Published Jun 2, 2026 · Updated Jun 2, 2026

Reflected XSS in authentik 2025.12.4 and earlier and 2026.2.0 through 2026.2.2 allows remote attackers to hijack SSO sessions. The SFE AutosubmitStage passes redirect_uri or state values to jQuery without explicit sanitization, allowing script execution in the browser. Exploitation requires user interaction and an OAuth2 provider; redirect_uri attacks also require a broad allowed-redirect regex, and impact includes token-bearing request redirection and session takeover.

CVSS severity9.3
Critical
EPSS probability0.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in authentik 2025.12.4 and earlier and 2026.2.0 through 2026.2.2 allows remote attackers to hijack SSO sessions. The SFE AutosubmitStage passes redirect_uri or state values to jQuery without explicit sanitization, allowing script execution in the browser. Exploitation requires user interaction and an OAuth2 provider; redirect_uri attacks also require a broad allowed-redirect regex, and impact includes token-bearing request redirection and session takeover.

The record

CVE
CVE-2026-42849
Published
Jun 2, 2026
Updated
Jun 2, 2026
Vendor
Authentik Security Inc.
Product
authentik
Classifications
CWE-79, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 2, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 2, 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=< 2025.12.5
  2. Affected versionversion=< 2026.2.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Authentik Security Inc. · authentikversion=< 2025.12.5; version=< 2026.2.3

Published CVSS scores

9.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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')
T1189Drive-by Compromise

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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