NVD / CVE Program· CNA Document Fdn.

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

Noroxi assessment

Priority: Monitor (action score 20/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.13% (FIRST EPSS).
Someone with local access to the system can trigger it. No account or password is required. Special conditions such as timing or configuration are required.
Fixed version: The Document Foundation LibreOffice 7.0.5, 7.1.1.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to The Document Foundation LibreOffice 7.0.5, 7.1.1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 5.2 · v4.0—No exploit Fix available

Weak crypto

Published: Mar 21, 2025
Updated: Jun 16, 2026
EPSS: 0.1% · 3th percentile
CWE: CWE-295

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 20 / 40 · 5.2 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.1%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · Document Fdn.: 5.2; NVD has not scored this yet; the score shown is the CNA’s.

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
libreoffice	libreoffice	cpe:2.3:a:libreoffice:libreoffice

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Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

libreoffice libreoffice7.0.0 and later · before 7.0.5.1
libreoffice libreoffice7.1.0.0 and later · up to 7.1.1.1 inclusive

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Document Fdn.). Independent of NVD's CPE analysis and usually ahead of it.

The Document Foundation LibreOffice
- 7.0 and later · before 7.0.5affected · 7.0 series
- 7.1 and later · before 7.1.1affected · 7.1 series

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
AlmaLinux:8	autocorr-af	before 1:6.4.7.2-10.el8.alma	1:6.4.7.2-10.el8.alma
AlmaLinux:8	autocorr-bg	before 1:6.4.7.2-10.el8.alma	1:6.4.7.2-10.el8.alma
AlmaLinux:8	autocorr-ca	before 1:6.4.7.2-10.el8.alma	1:6.4.7.2-10.el8.alma
AlmaLinux:8	autocorr-cs	before 1:6.4.7.2-10.el8.alma	1:6.4.7.2-10.el8.alma
AlmaLinux:8	autocorr-da	before 1:6.4.7.2-10.el8.alma	1:6.4.7.2-10.el8.alma
AlmaLinux:8	autocorr-de	before 1:6.4.7.2-10.el8.alma	1:6.4.7.2-10.el8.alma
AlmaLinux:8	autocorr-en	before 1:6.4.7.2-10.el8.alma	1:6.4.7.2-10.el8.alma
AlmaLinux:8	autocorr-es	before 1:6.4.7.2-10.el8.alma	1:6.4.7.2-10.el8.alma
AlmaLinux:8	autocorr-fa	before 1:6.4.7.2-10.el8.alma	1:6.4.7.2-10.el8.alma
AlmaLinux:8	autocorr-fi	before 1:6.4.7.2-10.el8.alma	1:6.4.7.2-10.el8.alma
AlmaLinux:8	autocorr-fr	before 1:6.4.7.2-10.el8.alma	1:6.4.7.2-10.el8.alma
AlmaLinux:8	autocorr-ga	before 1:6.4.7.2-10.el8.alma	1:6.4.7.2-10.el8.alma
AlmaLinux:8	autocorr-hr	before 1:6.4.7.2-10.el8.alma	1:6.4.7.2-10.el8.alma
AlmaLinux:8	autocorr-hu	before 1:6.4.7.2-10.el8.alma	1:6.4.7.2-10.el8.alma
AlmaLinux:8	autocorr-is	before 1:6.4.7.2-10.el8.alma	1:6.4.7.2-10.el8.alma
AlmaLinux:8	autocorr-it	before 1:6.4.7.2-10.el8.alma	1:6.4.7.2-10.el8.alma
AlmaLinux:8	autocorr-ja	before 1:6.4.7.2-10.el8.alma	1:6.4.7.2-10.el8.alma
AlmaLinux:8	autocorr-ko	before 1:6.4.7.2-10.el8.alma	1:6.4.7.2-10.el8.alma
AlmaLinux:8	autocorr-lb	before 1:6.4.7.2-10.el8.alma	1:6.4.7.2-10.el8.alma
AlmaLinux:8	autocorr-lt	before 1:6.4.7.2-10.el8.alma	1:6.4.7.2-10.el8.alma
AlmaLinux:8	autocorr-mn	before 1:6.4.7.2-10.el8.alma	1:6.4.7.2-10.el8.alma
AlmaLinux:8	autocorr-nl	before 1:6.4.7.2-10.el8.alma	1:6.4.7.2-10.el8.alma
AlmaLinux:8	autocorr-pl	before 1:6.4.7.2-10.el8.alma	1:6.4.7.2-10.el8.alma
AlmaLinux:8	autocorr-pt	before 1:6.4.7.2-10.el8.alma	1:6.4.7.2-10.el8.alma

+96

Same product

libreoffice: all records

Other highest-scoring records for the same primary product.

CVE-2019-9851LibreLogo global-event script execution
62This week
CVE-2018-16858It was found that libreoffice before versions 6.0.7 and 6.1.3 was vulnerable to a directory traversal attack which could be used to execute
60This week
CVE-2018-10583An information disclosure vulnerability occurs when LibreOffice 6.0.3 and Apache OpenOffice Writer 4.1.5 automatically process and initiate
60This week

Published before and after this one in the same product

← EarlierCVE-2025-0514Feb 25, 2025 · Executable hyperlink Windows path targets executed unconditionally on activation
28Monitor
← EarlierCVE-2025-1080Mar 4, 2025 · Macro URL arbitrary script execution
28Monitor
Later →CVE-2025-2866Apr 27, 2025 · PDF signature forgery with adbe.pkcs7.sha1 SubFilter
9Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
The Document Foundation LibreOffice	7.0.5	Vendor (CNA)
The Document Foundation LibreOffice	7.1.1	Vendor (CNA)
almalinux:autocorr-af	1:6.4.7.2-10.el8.alma · AlmaLinux:8	Package registry (OSV)
almalinux:autocorr-bg	1:6.4.7.2-10.el8.alma · AlmaLinux:8	Package registry (OSV)
almalinux:autocorr-ca	1:6.4.7.2-10.el8.alma · AlmaLinux:8	Package registry (OSV)
almalinux:autocorr-cs	1:6.4.7.2-10.el8.alma · AlmaLinux:8	Package registry (OSV)
almalinux:autocorr-da	1:6.4.7.2-10.el8.alma · AlmaLinux:8	Package registry (OSV)
almalinux:autocorr-de	1:6.4.7.2-10.el8.alma · AlmaLinux:8	Package registry (OSV)
almalinux:autocorr-en	1:6.4.7.2-10.el8.alma · AlmaLinux:8	Package registry (OSV)
almalinux:autocorr-es	1:6.4.7.2-10.el8.alma · AlmaLinux:8	Package registry (OSV)
almalinux:autocorr-fa	1:6.4.7.2-10.el8.alma · AlmaLinux:8	Package registry (OSV)
almalinux:autocorr-fi	1:6.4.7.2-10.el8.alma · AlmaLinux:8	Package registry (OSV)
almalinux:autocorr-fr	1:6.4.7.2-10.el8.alma · AlmaLinux:8	Package registry (OSV)
almalinux:autocorr-ga	1:6.4.7.2-10.el8.alma · AlmaLinux:8	Package registry (OSV)
red hat:autocorr-af	1:6.4.7.2-10.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
red hat:autocorr-bg	1:6.4.7.2-10.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
red hat:autocorr-ca	1:6.4.7.2-10.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
red hat:autocorr-cs	1:6.4.7.2-10.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
red hat:autocorr-da	1:6.4.7.2-10.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
red hat:autocorr-de	1:6.4.7.2-10.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
red hat:autocorr-en	1:6.4.7.2-10.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
red hat:autocorr-es	1:6.4.7.2-10.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
red hat:autocorr-fa	1:6.4.7.2-10.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
red hat:autocorr-fi	1:6.4.7.2-10.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
red hat:autocorr-fr	1:6.4.7.2-10.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
red hat:autocorr-ga	1:6.4.7.2-10.el8 · Red Hat:enterprise_linux:8::appstream	Package registry (OSV)
rocky linux:libreoffice	1:6.4.7.2-10.el8 · Rocky Linux:8	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

NDSRuhr University Bochumfinder

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

CVE-2024-5261269 days apartTLS certificate are not properly verified when utilizing LibreOfficeKit
40Plan
CVE-2024-6472228 days apartAbility to trust not validated macro signatures removed in high security mode
31Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

TR-21-0826 · Oct 12, 2021(OpenOffice Güvenlik Zafiyeti)

All national notices →

Technical details

Attack conditions

Someone with local access to the system can trigger it.
No account or password is required.
Special conditions such as timing or configuration are required.

If successful

Confidentiality
Integrity
Availability

Attack vector: Local
Attack complexity: High
Privileges required: None
User interaction: P
Scope: X

Weakness class (CWE)

CWE-295 · Improper Certificate Validation

CVSS 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Root cause

A certificate validation error is silently swallowed instead of terminating the connection. Often, code added for a test environment makes its way into production.

The bug in code

The whole CWE-295 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

kotlin

1override fun checkServerTrusted(chain: Array<X509Certificate>, type: String) {
2  // Left empty for the test environment
3}

Fixed

kotlin

1val client = OkHttpClient.Builder()
2  .certificatePinner(
3    CertificatePinner.Builder()
4      .add("api.sirius.example", "sha256/…")
5      .build()
6  ).build()

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

—

Change log

Fix✗ → ✓Sep 28, 2026, 10:10 PM UTC

For records you follow, these changes also arrive as notifications. →

References

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

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records