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CVE-2021-25633· NVD / CVE Program· CNA Document Fdn.

Content Manipulation with Double Certificate Attack

LibreOffice supports digital signatures of ODF documents and macros within documents, presenting visual aids that no alteration of the document occurred since the last signing and that the signature is valid. An Improper Certificate Validation vulnerability in LibreOffice allowed an attacker to create a digitally signed ODF document, by manipulating the documentsignatures.xml or macrosignatures.xml stream within the document to combine multiple certificate data, which when opened caused LibreOffice to display a validly signed indicator but whose content was unrelated to the signature shown. This issue affects: The Document Foundation LibreOffice 7-0 versions prior to 7.0.6; 7-1 versions prior to 7.1.2.

HighCVSS 7.5 · v3.1—No exploit Fix available

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Published
Oct 11, 2021
Updated
Jun 16, 2026
EPSS
0.7% · 53th percentile
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Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.7%

Affected systems

VendorProduct
libreofficelibreoffice
debiandebian linux

Affected versions

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

  • debian debian linux11.0
  • libreoffice libreoffice7.0.0 and later · before 7.0.6
  • libreoffice libreoffice7.1.0 and later · before 7.1.2

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 7.0.6affected
    • 7-1 and later · before 7.1.2affected

Package-level exposure

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

EcosystemPackageAffected rangeFix
AlmaLinux:8autocorr-afbefore 1:6.4.7.2-10.el8.alma1:6.4.7.2-10.el8.alma
AlmaLinux:8autocorr-bgbefore 1:6.4.7.2-10.el8.alma1:6.4.7.2-10.el8.alma
AlmaLinux:8autocorr-cabefore 1:6.4.7.2-10.el8.alma1:6.4.7.2-10.el8.alma
AlmaLinux:8autocorr-csbefore 1:6.4.7.2-10.el8.alma1:6.4.7.2-10.el8.alma
AlmaLinux:8autocorr-dabefore 1:6.4.7.2-10.el8.alma1:6.4.7.2-10.el8.alma
AlmaLinux:8autocorr-debefore 1:6.4.7.2-10.el8.alma1:6.4.7.2-10.el8.alma
AlmaLinux:8autocorr-enbefore 1:6.4.7.2-10.el8.alma1:6.4.7.2-10.el8.alma
AlmaLinux:8autocorr-esbefore 1:6.4.7.2-10.el8.alma1:6.4.7.2-10.el8.alma
AlmaLinux:8autocorr-fabefore 1:6.4.7.2-10.el8.alma1:6.4.7.2-10.el8.alma
AlmaLinux:8autocorr-fibefore 1:6.4.7.2-10.el8.alma1:6.4.7.2-10.el8.alma
AlmaLinux:8autocorr-frbefore 1:6.4.7.2-10.el8.alma1:6.4.7.2-10.el8.alma
AlmaLinux:8autocorr-gabefore 1:6.4.7.2-10.el8.alma1:6.4.7.2-10.el8.alma
AlmaLinux:8autocorr-hrbefore 1:6.4.7.2-10.el8.alma1:6.4.7.2-10.el8.alma
AlmaLinux:8autocorr-hubefore 1:6.4.7.2-10.el8.alma1:6.4.7.2-10.el8.alma
AlmaLinux:8autocorr-isbefore 1:6.4.7.2-10.el8.alma1:6.4.7.2-10.el8.alma
AlmaLinux:8autocorr-itbefore 1:6.4.7.2-10.el8.alma1:6.4.7.2-10.el8.alma
AlmaLinux:8autocorr-jabefore 1:6.4.7.2-10.el8.alma1:6.4.7.2-10.el8.alma
AlmaLinux:8autocorr-kobefore 1:6.4.7.2-10.el8.alma1:6.4.7.2-10.el8.alma
AlmaLinux:8autocorr-lbbefore 1:6.4.7.2-10.el8.alma1:6.4.7.2-10.el8.alma
AlmaLinux:8autocorr-ltbefore 1:6.4.7.2-10.el8.alma1:6.4.7.2-10.el8.alma
AlmaLinux:8autocorr-mnbefore 1:6.4.7.2-10.el8.alma1:6.4.7.2-10.el8.alma
AlmaLinux:8autocorr-nlbefore 1:6.4.7.2-10.el8.alma1:6.4.7.2-10.el8.alma
AlmaLinux:8autocorr-plbefore 1:6.4.7.2-10.el8.alma1:6.4.7.2-10.el8.alma
AlmaLinux:8autocorr-ptbefore 1:6.4.7.2-10.el8.alma1:6.4.7.2-10.el8.alma

+96

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
    59Plan
  • CVE-2018-10583An information disclosure vulnerability occurs when LibreOffice 6.0.3 and Apache OpenOffice Writer 4.1.5 automatically process and initiate
    54Plan
  • CVE-2019-9848LibreOffice has a feature where documents can specify that pre-installed scripts can be executed on various document events such as mouse-ov
    48Plan
  • CVE-2018-6871LibreOffice before 5.4.5 and 6.x before 6.0.1 allows remote attackers to read arbitrary files via =WEBSERVICE calls in a document, which use
    46Plan
  • CVE-2023-1183Arbitrary file write
    41Plan

Remediation

Which version to upgrade to

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

Product / packageFixed versionSource
almalinux:autocorr-af1:6.4.7.2-10.el8.alma · AlmaLinux:8Package registry (OSV)
almalinux:autocorr-bg1:6.4.7.2-10.el8.alma · AlmaLinux:8Package registry (OSV)
almalinux:autocorr-ca1:6.4.7.2-10.el8.alma · AlmaLinux:8Package registry (OSV)
almalinux:autocorr-cs1:6.4.7.2-10.el8.alma · AlmaLinux:8Package registry (OSV)
almalinux:autocorr-da1:6.4.7.2-10.el8.alma · AlmaLinux:8Package registry (OSV)
almalinux:autocorr-de1:6.4.7.2-10.el8.alma · AlmaLinux:8Package registry (OSV)
almalinux:autocorr-en1:6.4.7.2-10.el8.alma · AlmaLinux:8Package registry (OSV)
almalinux:autocorr-es1:6.4.7.2-10.el8.alma · AlmaLinux:8Package registry (OSV)
almalinux:autocorr-fa1:6.4.7.2-10.el8.alma · AlmaLinux:8Package registry (OSV)
almalinux:autocorr-fi1:6.4.7.2-10.el8.alma · AlmaLinux:8Package registry (OSV)
almalinux:autocorr-fr1:6.4.7.2-10.el8.alma · AlmaLinux:8Package registry (OSV)
almalinux:autocorr-ga1:6.4.7.2-10.el8.alma · AlmaLinux:8Package registry (OSV)
debian:libreoffice1:7.2.0-2 · Debian:12Package registry (OSV)
red hat:autocorr-af1:6.4.7.2-10.el8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:autocorr-bg1:6.4.7.2-10.el8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:autocorr-ca1:6.4.7.2-10.el8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:autocorr-cs1:6.4.7.2-10.el8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:autocorr-da1:6.4.7.2-10.el8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:autocorr-de1:6.4.7.2-10.el8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:autocorr-en1:6.4.7.2-10.el8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:autocorr-es1:6.4.7.2-10.el8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:autocorr-fa1:6.4.7.2-10.el8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:autocorr-fi1:6.4.7.2-10.el8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:autocorr-fr1:6.4.7.2-10.el8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:autocorr-ga1:6.4.7.2-10.el8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
rocky linux:libreoffice1:6.4.7.2-10.el8 · Rocky Linux:8Package 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.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

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.

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

  • NDSRuhr University Bochum

Variant candidates

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

No nightly-computed relations.

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).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
high · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
High
Availability impact
None

CVSS vector

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

nvd-primary

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.

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

Vulnerable

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

Fixed

kotlin
val client = OkHttpClient.Builder()  .certificatePinner(    CertificatePinner.Builder()      .add("api.sirius.example", "sha256/…")      .build()  ).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.

Change log

  1. Fix✗ → ✓

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

References

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

All records