CVE-2021-3199 - ONLYOFFICE Docs Server Path Traversal Vulnerability (known exploited)
Added to CISA KEV on 2026-10-08. ONLYOFFICE Docs contains a path traversal vulnerability that can occur when JWT is used, via a /.. sequence in an image upload parameter and could allow for remote code execution.
CRITICAL
CISA KEV
ACTIVELY EXPLOITED
Severity & confidence
Source severitycritical
Platform severitycritical
Confidencehigh
Exploitationactively exploited
CVSS-
Affected
ProductsDocs
Reporting sources (1)
CISA - Known Exploited Vulnerabilities
๐ฏ Why should I care?
- On the CISA Known Exploited Vulnerabilities list.
- Credible sources report active exploitation in the wild.
Timeline & provenance
Published2026-10-08T00:00:00
Last updated2026-10-21T04:58:05
Ingested2026-10-08T17:42:24
FreshnessNEAR-REAL-TIME
Threat typeexploitation
Recommended action
Apply the vendor-supplied patch immediately. Review vendor and CISA guidance for detection and mitigation.
Next steps
- Identify affected systems in your environment.
- Apply the vendor patch or mitigation guidance.
- Review logs for indicators described in the advisory.
- Follow the affected vendor/product to track updates.
Confidence explanation
Reported by a government or cert-grade source (CISA, NCSC, NVD, ENISA, MSRC).
Source type: gov ยท Original: CISA - Known Exploited Vulnerabilities
