CVE-2023-37913: org.xwiki.platform:xwiki-platform-office-importer vulnerable to arbitrary server side file writing from account through office converter

Should you act?

Critical, preconditions apply

Severe if exploited, but exploitation needs conditions that may not apply to you. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 1.1%, percentile 65: FIRST’s model estimates a 1.1% chance of exploitation activity in the next 30 days, higher than 65% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
• Needs an account (low (any account)). Exposure depends on who can log in.
• Only applies if your dependency tree includes org.xwiki.platform:xwiki-platform-office-importer (Maven) >= 3.5-milestone-1, < 14.10.8, fixed in 14.10.8; org.xwiki.platform:xwiki-platform-office-importer (Maven) >= 15.0-rc-1, < 15.3-rc-1, fixed in 15.3-rc-1. Check your lockfile, including transitive dependencies.

What it is

XWiki Platform is a generic wiki platform offering runtime services for applications built on top of it. Starting in version 3.5-milestone-1 and prior to versions 14.10.8 and 15.3-rc-1, triggering the office converter with a specially crafted file name allows writing the attachment's content to an attacker-controlled location on the server as long as the Java process has write access to that location. In particular in the combination with attachment moving, a feature introduced in XWiki 14.0, this is easy to reproduce but it also possible to reproduce in versions as old as XWiki 3.5 by uploading the attachment through the REST API which doesn't remove / or \ from the filename. As the mime type of the attachment doesn't matter for the exploitation, this could e.g., be used to replace the jar-file of an extension which would allow executing arbitrary Java code and thus impact the confidentiality, integrity and availability of the XWiki installation. This vulnerability has been patched in XWiki 14.10.8 and 15.3RC1. There are no known workarounds apart from disabling the office converter.

From the GitHub advisory

Impact

Triggering the office converter with a specially crafted file name allows writing the attachment's content to an attacker-controlled location on the server as long as the Java process has write access to that location. In particular in the combination with attachment moving, a feature introduced in XWiki 14.0, this is easy to reproduce but it also possible to reproduce in versions as old as XWiki 3.5 by uploading the attachment through the REST API which doesn't remove / or \ from the filename. As the mime type of the attachment doesn't matter for the exploitation, this could e.g., be used to replace the jar-file of an extension which would allow executing arbitrary Java code and thus impact the confidentiality, integrity and availability of the XWiki installation. To reproduce the issue on versions since XWiki 14.0, execute the following steps:

1. Activate the office server 2. Upload an arbitrary file with the extension .doc, e.g., to your user profile (you can use a regular plain text file, only the extension matters). 3. Use the attachment move feature to rename the file to ../../../../../tmp/Hello from XWiki.txt where the latter part is the location of a file you want to write on the server. The number of ../ depends on the directory depth, the provided example should work on Linux with the demo distribution. 4. Click the "preview" link to trigger the office converter

For information how to reproduce on older versions, see the Jira issue.

To the best of our knowledge, this attack is not possible when the office conversion process doesn't run as the code fails before the file is written.

Weakness type: CWE-23, CWE-22.

Product: org.xwiki.platform:xwiki-platform-office-importer (Maven) · Assigned by: GitHub_M · Published: 2023-10-25

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: low (any account)
• User interaction: none
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation poc, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 1.08% probability of exploitation activity in the next 30 days; percentile 65.

Timeline

• 2023-10-25 — CVE record published by GitHub_M
• 2023-10-25 — GitHub-reviewed advisory GHSA-vcvr-v426-3m3m published (critical)
• 2024-09-12 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-vcvr-v426-3m3m github.com
2. CVE.org record CVE-2023-37913 cve.org
3. NVD entry CVE-2023-37913 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. jira.xwiki.org jira.xwiki.org

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