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No exploitation reportedFix available

CVE-2026-33525

No exploitation reported by the sources we read.

  • Published2026-03-26
  • WeaknessCWE-79

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

Authelia is an open-source authentication and authorization server providing two-factor authentication and single sign-on (SSO) for applications via a web portal. In version 4.39.15, an attacker may potentially be able to inject javascript into the Authelia login page if several conditions are met simultaneously. Unless both the `script-src` and `connect-src` directives have been modified it's almost impossible for this to have a meaningful impact. However if both of these are and they are done so without consideration to their potential impact; there is a are situations where this vulnerability could be exploited. This is caused to the lack of neutralization of the `langauge` cookie value when rendering the HTML template. This vulnerability is likely difficult to discover though fingerprinting due to the way Authelia is designed but it should not be considered impossible. The additional requirement to identify the secondary application is however likely to be significantly harder to identify along side this, but also likely easier to fingerprint. Users should upgrade to 4.39.16 or downgrade to 4.39.14 to mitigate the issue. The overwhelming majority of installations will not be affected and no workarounds are necessary. The default value for the Content Security Policy makes exploiting this weakness completely impossible. It's only possible via the deliberate removal of the Content Security Policy or deliberate inclusion of clearly noted unsafe policies.

Timeline

dates in UTC
  1. 2026-03-2620:16CVE publishedNVD

Versions per branch

OSV · NVD
authelia/authelia
BranchAffectedFixed in
—all versionsno fix published
authelia/authelia
BranchAffectedFixed in
4.39≥ 4.39.15, < 4.39.164.39.16
Authelia
BranchAffectedFixed in
4.39= 4.39.15no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As GitHub_M, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • authelia
    Affected
    • = = 4.39.15no fix stated

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-03-26

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • govulncheck-vulndbopenSUSE:Leap 16.0all versions · fixed in 0.0.20260723T184607-160000.1.1
  • govulncheck-vulndbopenSUSE:Leap 15.6all versions · fixed in 0.0.20260326T203309-150000.1.155.2

Full record on NVD

Fix

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • CISA-ADPSSVC decisionnone2026-03-30
  • CNACVSS 4.00.5known since 2026-10-23
  • NVDCVSS 3.16.1read 2026-10-23
  • CNAweakness (CWE)CWE-79known since 2026-10-23
  • FIRST EPSSEPSS score0.2 %2026-11-09
  • OSVaffected packages—
  • GitHub AdvisoriesadvisoryLOW2026-03-24

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CVSS 4.0 vector
CVSS:4.0/AV:A/AC:H/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Published
2026-03-26
Last Modified
2026-06-17
NVD status
Analyzed
GitHub Advisory
GHSA-gmfg-3v4q-9qr4

Frequently asked questions

What is CVE-2026-33525?

Authelia is an open-source authentication and authorization server providing two-factor authentication and single sign-on (SSO) for applications via a web portal. In version 4.39.15, an attacker may potentially be able to inject javascript into the Authelia login page if several conditions are met simultaneously. Unless both the `script-src` and `connect-src` directives have been modified it's almost impossible for this to have a meaningful impact. However if both of these are and they are done so without consideration to their potential impact; there is a are situations where this vulnerability could be exploited. This is caused to the lack of neutralization of the `langauge` cookie value when rendering the HTML template. This vulnerability is likely difficult to discover though fingerprinting due to the way Authelia is designed but it should not be considered impossible. The additional requirement to identify the secondary application is however likely to be significantly harder to identify along side this, but also likely easier to fingerprint. Users should upgrade to 4.39.16 or downgrade to 4.39.14 to mitigate the issue. The overwhelming majority of installations will not be affected and no workarounds are necessary. The default value for the Content Security Policy makes exploiting this weakness completely impossible. It's only possible via the deliberate removal of the Content Security Policy or deliberate inclusion of clearly noted unsafe policies.

Is CVE-2026-33525 actively exploited?

Active exploitation of CVE-2026-33525 has not been confirmed. Its EPSS score was 0.2% on 2026-11-09, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-33525?

CVE-2026-33525 has a CVSS v3 base score of 6.1 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

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