How severe is CVE-2023-35156?

CVE-2023-35156 has a CVSS score of 9.6/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2023-35156?

CVE-2023-35156 affects the following packages: org.xwiki.platform:xwiki-platform-flamingo-skin-resources (Maven), org.xwiki.platform:xwiki-platform-flamingo-skin-resources (Maven). Ecosystems affected: Maven.

How do I fix CVE-2023-35156?

Update org.xwiki.platform:xwiki-platform-flamingo-skin-resources to 14.10.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-35156 is resolved across your whole dependency graph.

How do I detect CVE-2023-35156 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.xwiki.platform:xwiki-platform-flamingo-skin-resources, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2023-35156 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2023-35156 actively exploited in the wild?

No public exploit code has been indexed for CVE-2023-35156 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2023-35156?

CVE-2023-35156 has an EPSS (Exploit Prediction Scoring System) score of 2.1%, placing it in the 82th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2023-35156?

CVE-2023-35156 is classified as CWE-87 (CWE-87), Cross-site Scripting (XSS) (CWE-79). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

Is there exploit tooling available for CVE-2023-35156?

A Nuclei detection template exists for CVE-2023-35156, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2023-35156 published, and has it been updated?

CVE-2023-35156 was published on June 23, 2023 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

CRITICAL severity

CVE-2023-35156 — xwiki-platform-flamingo-s…

CRITICALFix: xwiki/xwiki-platform@13875a6

CVE-2023-35156 is a critical-severity (CVSS 9.6) CWE-87 vulnerability in org.xwiki.platform:xwiki-platform-flamingo-skin-resources. A fix is available for org.xwiki.platform:xwiki-platform-flamingo-skin-resources — see the affected versions and patch details below.

XWiki Platform vulnerable to reflected cross-site scripting via xredirect parameter in delete template

Also known asGHSA-834c-x29c-f42c

Published

Jun 23, 2023

Updated

Oct 28, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Nov 5, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA’s SSVC triage for CVE-2023-35156.

EPSS Exploitation Probability

via FIRST.org ↗

2.1%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs82th percentile — riskier than 82% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

2 pkgs affected

☕org.xwiki.platform:xwiki-platform-flamingo-skin-resources☕org.xwiki.platform:xwiki-platform-flamingo-skin-resources

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

Impact

Users are able to forge an URL with a payload allowing to inject Javascript in the page (XSS). It's possible to exploit the delete template to perform a XSS, e.g. by using URL such as:

xwiki/bin/get/FlamingoThemes/Cerulean?xpage=xpart&vm=delete.vm&xredirect=javascript:alert(document.domain)

This vulnerability exists since XWiki 6.0-rc-1.

Patches

The vulnerability has been patched in XWiki 14.10.6 and 15.1. Note that a partial patch has been provided in 14.10.5 but wasn't enough to entirely fix the vulnerability.

Workarounds

It's possible to workaround the vulnerability by editing the template delete.vm to perform checks on it, but note that the appropriate fix involves new APIs that have been recently introduced in XWiki. See the referenced jira tickets.

References

Jira ticket about the original vulnerability: https://jira.xwiki.org/browse/XWIKI-20341
Commit containing the first fix in the template: https://github.com/xwiki/xwiki-platform/commit/e80d22d193df364b07bab7925572720f91a8984a
Jira ticket about the second part of the vulnerability found after 14.10.5: https://jira.xwiki.org/browse/XWIKI-20672
Commits containing the second fix in the template:
- https://github.com/xwiki/xwiki-platform/commit/13875a6437d4525ac4aeea25918f2d2dffac9ee1
- https://github.com/xwiki/xwiki-platform/commit/24ec12890ac7fa6daec8d0b3435cfcba11362fd5
Introduction of the macro used for fixing all those vulnerabilities: https://jira.xwiki.org/browse/XWIKI-20583

For more information

If you have any questions or comments about this advisory:

Open an issue in Jira XWiki.org
Email us at Security Mailing List

Attribution

This vulnerability has been reported by René de Sain @renniepak.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.xwiki.platform:xwiki-platform-flamingo-skin-resources`	≥ 6.0-rc-1&&< 14.10.6	14.10.6`org.xwiki.platform:xwiki-platform-flamingo-skin-resources:14.10.6`
☕Maven	`org.xwiki.platform:xwiki-platform-flamingo-skin-resources`	≥ 15.0-rc-0&&< 15.1	15.1`org.xwiki.platform:xwiki-platform-flamingo-skin-resources:15.1`

Affected Products

1 product · 4 configurations

Application

xwikixwiki

≥ 6.0.1 && < 14.10.6

2 versions

6.015.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.xwiki.platform:xwiki-platform-flamingo-skin-resources, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.xwiki.platform:xwiki-platform-flamingo-skin-resources to 14.10.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-35156 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

How to detect CVE-2023-35156

A community-maintained Nuclei template exists for this CVE. You can scan for it directly:

nuclei -id cve-2023-35156 -u https://target

Template: XWiki >= 6.0-rc-1 - Cross-Site Scripting
Severity: medium
Impact: Successful exploitation could lead to cross-site scripting.
Remediation: This vulnerability has been patched in XWiki 14.10.6,15.1.

Template by ProjectDiscovery nuclei-templates (ritikchaddha), MIT licensed. View the full template. Scan only systems you are authorised to test.

Frequently Asked Questions

### Impact Users are able to forge an URL with a payload allowing to inject Javascript in the page (XSS). It's possible to exploit the delete template to perform a XSS, e.g. by using URL such as: > xwiki/bin/get/FlamingoThemes/Cerulean?xpage=xpart&vm=delete.vm&xredirect=javascript:alert(document.domain) This vulnerability exists since XWiki 6.0-rc-1. ### Patches The vulnerability has been patched in XWiki 14.10.6 and 15.1. Note that a partial patch has been provided in 14.10.5 but wasn't enough to entirely fix the vulnerability. ### Workarounds It's possible to workaround the vulnerabi