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Critical severity · published Mar 1, 2021
CVE-2021-25833
A file extension handling issue was found in [server] module of ONLYOFFICE DocumentServer v4.2.0.71-v5.6.0.21
9.8
CVSS
43.5%
EPSS
No
On KEV
Description
A file extension handling issue was found in [server] module of ONLYOFFICE DocumentServer v4.2.0.71-v5.6.0.21. The file extension is controlled by an attacker through the request data and leads to arbitrary file overwriting. Using this vulnerability, a remote attacker can obtain remote code execution on DocumentServer.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)43.5% · higher than 99% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
DS
Document Server · Onlyoffice
4.2.0.71 through 5.6.0.21 · source: NVD
Affected product
DS
Document Server
Onlyoffice
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-25833
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-25833
Product
https://github.com/ONLYOFFICE/DocumentServer
Product
https://github.com/ONLYOFFICE/server
Third Party Advisory
https://github.com/ONLYOFFICE/server/blob/v5.6.0.21/DocService/sources/converterservice.js#L200
Third Party Advisory
https://github.com/ONLYOFFICE/server/blob/v5.6.0.21/FileConverter/sources/converter.js#L283
Third Party Advisory
https://github.com/ONLYOFFICE/server/blob/v5.6.0.21/FileConverter/sources/converter.js#L593
Exploit
https://github.com/merrychap/poc_exploits/tree/master/ONLYOFFICE/CVE-2021-25833
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