A LibreOffice security update has been released for Ubuntu Linux 20.04 LTS.

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Ubuntu Security Notice USN-5153-1
November 22, 2021

libreoffice vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 20.04 LTS

Summary:

LibreOffice could incorrectly validate document signatures.

Software Description:
- libreoffice: Office productivity suite

Details:

It was discovered that LibreOffice incorrectly handled digital signatures.
An attacker could possibly use this issue to create a specially crafted
document that would display a validly signed indicator, contrary to
expectations.

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 20.04 LTS:
libreoffice-core 1:6.4.7-0ubuntu0.20.04.2

In general, a standard system update will make all the necessary changes.

References:
  https://ubuntu.com/security/notices/USN-5153-1
CVE-2021-25633, CVE-2021-25634

Package Information:
  https://launchpad.net/ubuntu/+source/libreoffice/1:6.4.7-0ubuntu0.20.04.2