CVE-2026-42849: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in goauthentik authentik
authentik is an open-source identity provider. Prior to versions 2025.12.5 and 2026.2.3, due to the implementation of stages in the SFE (Simple Flow Executor) in order to make the interface more compatible with legacy browsers, it was possible to use an XSS exploit in the AutosubmitStage. This issue has been patched in versions 2025.12.5 and 2026.2.3.
AI Analysis
Technical Summary
CVE-2026-42849 is a CWE-79 (Improper Neutralization of Input During Web Page Generation) vulnerability affecting authentik, an open-source identity provider. The vulnerability is due to the implementation of stages in the Simple Flow Executor (SFE), specifically in the AutosubmitStage, which allowed cross-site scripting (XSS) attacks. This flaw was introduced to improve compatibility with legacy browsers but resulted in unsafe input handling. The vulnerability is fixed in authentik versions 2025.12.5 and 2026.2.3.
Potential Impact
Successful exploitation of this vulnerability can lead to the execution of arbitrary scripts in the user's browser, potentially resulting in session hijacking, credential theft, or other malicious actions within the context of the authentik web interface. The CVSS v3.1 score is 9.3 (critical), reflecting network attack vector, low attack complexity, no privileges required, user interaction required, scope change, and high confidentiality and integrity impact with no availability impact.
Mitigation Recommendations
This vulnerability has been patched in authentik versions 2025.12.5 and 2026.2.3. Users should upgrade to at least one of these versions to remediate the issue. No additional mitigation steps are indicated by the vendor advisory.
CVE-2026-42849: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in goauthentik authentik
Description
authentik is an open-source identity provider. Prior to versions 2025.12.5 and 2026.2.3, due to the implementation of stages in the SFE (Simple Flow Executor) in order to make the interface more compatible with legacy browsers, it was possible to use an XSS exploit in the AutosubmitStage. This issue has been patched in versions 2025.12.5 and 2026.2.3.
CVSS v3.1
Score 9.3critical
Affected software
pkg:golang/github.com/goauthentik/authentikRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-42849 is a CWE-79 (Improper Neutralization of Input During Web Page Generation) vulnerability affecting authentik, an open-source identity provider. The vulnerability is due to the implementation of stages in the Simple Flow Executor (SFE), specifically in the AutosubmitStage, which allowed cross-site scripting (XSS) attacks. This flaw was introduced to improve compatibility with legacy browsers but resulted in unsafe input handling. The vulnerability is fixed in authentik versions 2025.12.5 and 2026.2.3.
Potential Impact
Successful exploitation of this vulnerability can lead to the execution of arbitrary scripts in the user's browser, potentially resulting in session hijacking, credential theft, or other malicious actions within the context of the authentik web interface. The CVSS v3.1 score is 9.3 (critical), reflecting network attack vector, low attack complexity, no privileges required, user interaction required, scope change, and high confidentiality and integrity impact with no availability impact.
Mitigation Recommendations
This vulnerability has been patched in authentik versions 2025.12.5 and 2026.2.3. Users should upgrade to at least one of these versions to remediate the issue. No additional mitigation steps are indicated by the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-30T16:44:48.378Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a1f41c3e29bf47b5000d19e
Added to database: 06/02/2026, 20:49:07 UTC
Last enriched: 06/10/2026, 11:03:28 UTC
Last updated: 07/31/2026, 19:22:58 UTC
Views: 59
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