CVE-2022-39338Network attack vector

Stored XSS via unvalidated authorization endpoint

Published Nov 25, 2022 · Updated Apr 23, 2025

Stored XSS in Nextcloud user_oidc before 1.2.1 allows remote authenticated users to run script in a user's browser via a malicious discovery URL. The Safari login path inserts the discovery document's authorization_endpoint value into an HTML meta refresh without first validating the URL. Exploitation requires control of OpenID provider configuration and a Safari user to begin OIDC login, while the restrictive CSP limits resulting access.

CVSS severity3.5
Low
EPSS probability0.61%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Nextcloud user_oidc before 1.2.1 allows remote authenticated users to run script in a user's browser via a malicious discovery URL. The Safari login path inserts the discovery document's authorization_endpoint value into an HTML meta refresh without first validating the URL. Exploitation requires control of OpenID provider configuration and a Safari user to begin OIDC login, while the restrictive CSP limits resulting access.

The record

CVE
CVE-2022-39338
Published
Nov 25, 2022
Updated
Apr 23, 2025
Vendor
Nextcloud GmbH
Product
Security Advisories
Classifications
CWE-79, CWE-20, T1059.007
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Nov 25, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 23, 2025Record 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=< 1.2.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Nextcloud GmbH · Security Advisoriesversion=< 1.2.1

Published CVSS scores

3.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:L/A:N
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-20Improper Input Validation
T1059.007JavaScript/JScript

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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