CVE-2021-25831

Public Exploit

Description

A file extension handling issue was found in [core] module of ONLYOFFICE DocumentServer v4.0.0-9-v5.6.3. An attacker must request the conversion of the crafted file from PPTT into PPTX format. Using the chain of two other bugs related to improper string handling, a remote attacker can obtain remote code execution on DocumentServer.

9.8

CVSS

Severity: Critical

CVSS 3.1 •

CVSS 2.0 •

EPSS 3.62% Top 15%

Vendor Advisory github.com Vendor Advisory github.com Vendor Advisory github.com Vendor Advisory github.com Vendor Advisory github.com

Affected: n/a n/a

References

Link	Tags
https://github.com/ONLYOFFICE/DocumentServer	product
https://github.com/ONLYOFFICE/core	product vendor advisory
https://github.com/ONLYOFFICE/core/blob/v5.6.4.13/ASCOfficePPTXFile/Editor/BinaryFileReaderWriter.cpp#L241	vendor advisory
https://github.com/ONLYOFFICE/core/blob/v5.6.4.13/ASCOfficePPTXFile/Editor/BinaryFileReaderWriter.cpp#L1918	vendor advisory
https://github.com/ONLYOFFICE/core/blob/v5.6.4.13/ASCOfficePPTXFile/PPTXFormat/Logic/Fills/BlipFill.cpp#L328	vendor advisory
https://github.com/merrychap/poc_exploits/tree/master/ONLYOFFICE/CVE-2021-25831	vendor advisory exploit

Frequently Asked Questions

What is the severity of CVE-2021-25831?: CVE-2021-25831 has been scored as a critical severity vulnerability.
How to fix CVE-2021-25831?: To fix CVE-2021-25831, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-25831 being actively exploited in the wild?: It is possible that CVE-2021-25831 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~4% probability that this vulnerability will be exploited by malicious actors in the next 30 days.

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