CVE-2025-2866: libreoffice Signature Bypass — Fix

Description

Improper Verification of Cryptographic Signature vulnerability in LibreOffice allows PDF Signature Spoofing by Improper Validation. In the affected versions of LibreOffice a flaw in the verification code for adbe.pkcs7.sha1 signatures could cause invalid signatures to be accepted as valid This issue affects LibreOffice: from 24.8 before < 24.8.6, from 25.2 before < 25.2.2.

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CVSS v3.1 Score

5.5

MEDIUM

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

Weakness Type (CWE)

CWE-347 CWE-347

Affected Products

Vendor	Product	Versions
libreoffice	libreoffice	24.8.0.1 — 24.8.6.0
libreoffice	libreoffice	25.2.0.1 — 25.2.2
libreoffice	libreoffice	All
libreoffice	libreoffice	All
libreoffice	libreoffice	All
libreoffice	libreoffice	All

References

Advisories & Patches

https://www.libreoffice.org/about-us/security/advisories/cve-2025-2866

Other References

https://lists.debian.org/debian-lts-announce/2025/06/msg00002.html

Frequently Asked Questions

What is CVE-2025-2866? +

Improper Verification of Cryptographic Signature vulnerability in LibreOffice allows PDF Signature Spoofing by Improper Validation. In the affected versions of LibreOffice a flaw in the verification code for adbe.pkcs7.sha1 signatures could cause invalid signatures to be accepted as valid This issue affects LibreOffice: from 24.8 before < 24.8.6, from 25.2 before < 25.2.2. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2025-2866? +

CVE-2025-2866 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-2866? +

CVE-2025-2866 affects products from libreoffice, specifically: libreoffice. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-2866? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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