CVE-2020-11535 — An issue was discovered in ONLYOFFICE Document Server 5

An issue was discovered in ONLYOFFICE Document Server 5.5.0. An attacker can craft a malicious .docx file, and exploit XML injection to enter an attacker-controlled parameter into the x2t binary, to rewrite this binary and/or libxcb.so.1, and execute code on a victim's serve

01What is this vulnerability?

An issue was discovered in ONLYOFFICE Document Server 5.5.0. An attacker can craft a malicious .docx file, and exploit XML injection to enter an attacker-controlled parameter into the x2t binary, to rewrite this binary and/or libxcb.so.1, and execute code on a victim's server.

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2020-04-15T14:56:21.000Z
• Last modified: 2024-08-04T11:35:12.979Z

09References

• github.com — https://github.com/ONLYOFFICE/DocumentServer/blob/master/CHANGELOG.md#551
• gist.github.com — https://gist.github.com/andrewaeva/beb92d3d2f1c5672dbda5050e323f6a0