CVE-2021-25634Network attack vector

Signing-time falsification via wrapped timestamp injection

Published Oct 12, 2021 · Updated Sep 17, 2024

Improper certificate validation in LibreOffice 7.0 before 7.0.6 and 7.1 before 7.1.2 allows attackers to falsify ODF signing times. The ODF signature validation and display path accepts an attacker-added timestamp in a wrapped signature and presents the bogus signing time as valid. Exploitation requires delivery of a modified, already-signed ODF document; the demonstrated consequence is false signature-time information, not code execution.

CVSS severity7.5
High
EPSS probability0.71%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper certificate validation in LibreOffice 7.0 before 7.0.6 and 7.1 before 7.1.2 allows attackers to falsify ODF signing times. The ODF signature validation and display path accepts an attacker-added timestamp in a wrapped signature and presents the bogus signing time as valid. Exploitation requires delivery of a modified, already-signed ODF document; the demonstrated consequence is false signature-time information, not code execution.

The record

CVE
CVE-2021-25634
Published
Oct 12, 2021
Updated
Sep 17, 2024
Vendor
The Document Foundation
Product
LibreOffice
Classifications
CWE-295, CAPEC-475, T1036
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 12, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=7-0 <7.0.6
  2. Affected versionversion=7-1 <7.1.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Document Foundation · LibreOfficeversion=7-0 <7.0.6; version=7-1 <7.1.2

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:P/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-295Improper Certificate Validation
CAPEC-475Signature Spoofing by Improper Validation
T1036Masquerading

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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