CVE-2021-41831Public exploitNetwork attack vector

Signed-document timestamp falsification via signature wrapping

Published Oct 11, 2021 · Updated Aug 4, 2024

Improper signature verification in Apache OpenOffice 4.1.10 and earlier allows remote attackers to falsify signed-document timestamps. ODF signature handling accepts an attacker-inserted signing-time timestamp outside the trusted signature data and displays the bogus time as valid. Exploitation requires a crafted, previously signed ODF document, and the result misrepresents when its trusted signer approved the content.

CVSS severity5.3
Medium
EPSS probability1.50%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper signature verification in Apache OpenOffice 4.1.10 and earlier allows remote attackers to falsify signed-document timestamps. ODF signature handling accepts an attacker-inserted signing-time timestamp outside the trusted signature data and displays the bogus time as valid. Exploitation requires a crafted, previously signed ODF document, and the result misrepresents when its trusted signer approved the content.

The record

CVE
CVE-2021-41831
Published
Oct 11, 2021
Updated
Aug 4, 2024
Vendor
The Apache Software Foundation
Product
Apache OpenOffice
Classifications
CWE-347, T1036
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 11, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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=Apache OpenOffice <=4.1.10
  2. Affected versionversion=OpenOffice.org <=3.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache OpenOfficeversion=Apache OpenOffice <=4.1.10; version=OpenOffice.org <=3.4

Published CVSS scores

5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature
T1036Masquerading

Public exploit references

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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