Vulnerability in Onlyoffice Document Server
CVE-2021-25830
A file extension handling issue was found in [core] module of ONLYOFFICE DocumentServer v4.2.0.236-v5.6.4.13. An attacker must request the conversion of the crafted file from DOCT into DOCX format. Using the chain of two other bugs related to improper string handling, an attacker can achieve remote code execution on DocumentServer.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.118 (95.9th percentile), scored .
Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 96th percentile — 95.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.118 · newest: 0.118 · change: 0.000
Affected products
Public proof-of-concept exploits
References
- github.com/ONLYOFFICE/DocumentServer (Product)
- github.com/ONLYOFFICE/core (Product)
- github.com/ONLYOFFICE/core/blob/v5.6.4.13/ASCOfficePPTXFile/PPTXFormat/Logic/Un… (Third Party Advisory)
- github.com/ONLYOFFICE/core/blob/v5.6.4.13/ASCOfficePPTXFile/Editor/BinaryFileRe… (Third Party Advisory)
- github.com/ONLYOFFICE/core/blob/v5.6.4.13/ASCOfficePPTXFile/Editor/BinaryFileRe… (Third Party Advisory)
- github.com/merrychap/poc_exploits/tree/master/ONLYOFFICE/CVE-2021-25830 (Exploit, Third Party Advisory)
Frequently asked questions
- What is CVE-2021-25830?
- CVE-2021-25830 is a critical-severity vulnerability in Onlyoffice Document Server. CVSS score: 9.8/10. Published 2021-03-01.
- How severe is CVE-2021-25830?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2021-25830 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.