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CVE-2021-25636

HIGHCVSS 7.5/10EPSS 0.97%

Last modified

CVE-2021-25636 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. LibreOffice supports digital signatures of ODF documents and macros within documents, presenting visual aids that no alteration of the document occurred since the last signing and that the signature is valid. An Improper Certificate Validation vulnerability in LibreOffice allowed an attacker to create a digitally signed ODF document, by manipulating the documentsignatures.xml or macrosignatures.xml stream within the document to contain both "X509Data" and "KeyValue" children of the "KeyInfo" tag, which when opened caused LibreOffice to verify using the "KeyValue" but to report verification with the unrelated "X509Data" value. EPSS estimates a 0.97% chance of exploitation in the next 30 days.

Description

LibreOffice supports digital signatures of ODF documents and macros within documents, presenting visual aids that no alteration of the document occurred since the last signing and that the signature is valid. An Improper Certificate Validation vulnerability in LibreOffice allowed an attacker to create a digitally signed ODF document, by manipulating the documentsignatures.xml or macrosignatures.xml stream within the document to contain both "X509Data" and "KeyValue" children of the "KeyInfo" tag, which when opened caused LibreOffice to verify using the "KeyValue" but to report verification with the unrelated "X509Data" value. This issue affects: The Document Foundation LibreOffice 7.2 versions prior to 7.2.5.

Metrics

CVSS 3.1
7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS Probability
0.97%

57.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
LibreofficeLibreoffice>= 7.2.0, < 7.2.5
FedoraprojectFedora34

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2021-25636?
LibreOffice supports digital signatures of ODF documents and macros within documents, presenting visual aids that no alteration of the document occurred since the last signing and that the signature is valid. An Improper Certificate Validation vulnerability in LibreOffice allowed an attacker to create a digitally signed ODF document, by manipulating the documentsignatures.xml or macrosignatures.xml stream within the document to contain both "X509Data" and "KeyValue" children of the "KeyInfo" tag, which when opened caused LibreOffice to verify using the "KeyValue" but to report verification with the unrelated "X509Data" value. This issue affects: The Document Foundation LibreOffice 7.2 versions prior to 7.2.5.
How severe is CVE-2021-25636?
CVE-2021-25636 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.97% probability of exploitation in the next 30 days.
How do I fix CVE-2021-25636?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-25636?

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Source: NVD / NIST