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Libreoffice CVE-2021-25635

MEDIUM
Improper Certificate Validation (CWE-295)
2025-03-21 security@documentfoundation.org
5.2
CVSS 4.0 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A07:2025 - Authentication Failures
ASVS 5.0
V12 - Secure Communication Certificate validation
Impact

CVSS score of 5.2 (MEDIUM). Attack characteristics: local attack vector, high complexity, no privileges required, user interaction required. EPSS exploitation probability: 0.05%.

Exploit ScenarioDerived

Successful exploitation could compromise the medium-severity affected system.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 28, 2026

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. Rated medium severity (CVSS 5.2), this vulnerability is no authentication required.

Earlier versions of this analysis (1)
v1 Mar 28, 2026 - 18:32 CVSS 5.2

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified under CWE-295. 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 person0 before 7.0.5, from 7.1 before 7.1.1. Affected products include: Libreoffice. Version information: before 7.0.5.

Severity by source

NVD PRIMARY 5.2 MEDIUM
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
SUSE 5.5 MEDIUM
AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Red Hat 6.3 MEDIUM

Primary rating from NVD.

CVSS VectorNVD

Attack Vector
Local
Attack Complexity
High
Attack Requirements
None
Privileges Required
None
User Interaction
Passive
Vulnerable system: Confidentiality
Low
Vulnerable system: Integrity
Low
Vulnerable system: Availability
None
Subsequent system: Confidentiality
High
Subsequent system: Integrity
High
Subsequent system: Availability
High

Lifecycle Timeline

2
Patch released
Apr 01, 2026 - 08:30 nvd
Patch available
CVE Published
Mar 21, 2025 - 15:15 nvd
MEDIUM 5.2

DescriptionCVE.org

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.

Executive ViewAI

Why It Matters

CVE-2021-25635 presents moderate security risk rated CVSS 5.2. Exploitation could compromise the security of affected deployments. Organizations should apply vendor updates when available and monitor for exploitation.

Business Impact: Low
Compensating Controls

Apply vendor patch. If patching is delayed: restrict network access and enable monitoring.

Threat Intelligence Overview

EPSS Score
0.1%
Top 84% exploitable
Data Quality
4 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.1%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Defer
Exploitation· derived
None
System Exposure· derived
Small
Automatable· derived
No
Human Impact
Low

Priority Score

26
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +26
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

Affected Products (CPE)CVE.org

cpe:2.3:a:libreoffice:libreoffice:*:*:*:*:*:*:*:*
cpe:2.3:a:libreoffice:libreoffice:*:*:*:*:*:*:*:*
CVE-2019-9851 CRITICAL POC
9.8 Aug 15

LibreOffice is typically bundled with LibreLogo, a programmable turtle vector graphics script, which can execute arbitra

CVE-2015-5212 MEDIUM
6.8 Nov 10

Integer underflow in LibreOffice before 4.4.5 and Apache OpenOffice before 4.1.2, when the configuration setting "Load p

CVE-2015-5214 MEDIUM
6.8 Nov 10

LibreOffice before 4.4.6 and 5.x before 5.0.1 and Apache OpenOffice before 4.1.2 allows remote attackers to cause a deni

CVE-2018-6871 CRITICAL POC
9.8 Feb 09

LibreOffice before 5.4.5 and 6.x before 6.0.1 allows remote attackers to read arbitrary files via =WEBSERVICE calls in a

CVE-2021-25631 HIGH POC
8.8 May 03

In the LibreOffice 7-1 series in versions prior to 7.1.2, and in the 7-0 series in versions prior to 7.0.5, the denylist

CVE-2012-2334 MEDIUM POC
6.8 Jun 19

Integer overflow in filter/source/msfilter/msdffimp.cxx in OpenOffice.org (OOo) 3.3, 3.4 Beta, and possibly earlier, and

CVE-2018-10583 HIGH POC
7.5 May 01

An information disclosure vulnerability occurs when LibreOffice 6.0.3 and Apache OpenOffice Writer 4.1.5 automatically p

CVE-2014-3524 CRITICAL
9.3 Aug 26

Apache OpenOffice before 4.1.1 allows remote attackers to execute arbitrary commands and possibly have other unspecified

CVE-2015-5213 MEDIUM
6.8 Nov 10

Integer overflow in LibreOffice before 4.4.5 and Apache OpenOffice before 4.1.2 allows remote attackers to cause a denia

CVE-2014-0247 CRITICAL
10.0 Jul 03

LibreOffice 4.2.4 executes unspecified VBA macros automatically, which has unspecified impact and attack vectors, possib

CVE-2012-0037 MEDIUM POC
6.5 Jun 17

Redland Raptor (aka libraptor) before 2.0.7, as used by OpenOffice 3.3 and 3.4 Beta, LibreOffice before 3.4.6 and 3.5.x

CVE-2017-7856 CRITICAL
9.8 Apr 14

LibreOffice before 2017-03-11 has an out-of-bounds write caused by a heap-based buffer overflow in the SVMConverter::Imp

Vendor StatusVendor

SUSE

Severity: Medium
Product Status
SUSE Linux Enterprise Server 12 SP5 Fixed
SUSE Linux Enterprise Server 15 SP3 Fixed
SUSE Linux Enterprise Server for SAP Applications 12 SP5 Fixed
SUSE Linux Enterprise Desktop 12 SP3 Fixed
SUSE Linux Enterprise Desktop 12 SP4 Fixed

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