How severe is CVE-2021-25635?

CVE-2021-25635 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2021-25635 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-25635?

CVE-2021-25635 affects Libreoffice. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-25635?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2021-25635 have an EU (EUVD) identifier?

Yes. CVE-2021-25635 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-12531.

When was CVE-2021-25635 published?

CVE-2021-25635 was published on 2025-03-21 and last updated on 2026-06-17.

CVE-2021-25635

CVE-2021-25635 is a medium-severity vulnerability in Libreoffice with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-295.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
CVSS v4: 5.2
EPSS exploit prediction: 0% (3rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2021-12531
Weakness: CWE-295
Affected product: Libreoffice
Published: 2025-03-21
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2021-25635?: 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.
How severe is CVE-2021-25635?: CVE-2021-25635 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2021-25635 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-25635?: CVE-2021-25635 affects Libreoffice. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-25635?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2021-25635 have an EU (EUVD) identifier?: Yes. CVE-2021-25635 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-12531.
When was CVE-2021-25635 published?: CVE-2021-25635 was published on 2025-03-21 and last updated on 2026-06-17.

References

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

Affected products (1)

cpe:2.3:a:libreoffice:libreoffice:*:*:*:*:*:*:*:*

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