Double Certificate Attack

published 2021-10-11 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-28831

cvss: 7.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.4%; EPSS 1.4% chance of exploitation in 30 days, percentile 72%
public exploits: 0; none known

It is possible for an attacker to manipulate signed documents and macros to appear to come from a trusted source. All versions of Apache OpenOffice up to 4.1.10 are affected. Users are advised to update to version 4.1.11. See CVE-2021-25633 for the LibreOffice advisory.

Patch / fix

fixed in 1

apache openoffice 4.1.11

Exploit prediction

1.39% chance of exploitation in the next 30 days, higher than 72% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD	2.0	5.0	AV:N/AC:L/Au:N/C:N/I:P/A:N

Affected products

Apache Software Foundation Apache OpenOffice

Classification

Weakness

CWE-347 Improper Verification of Cryptographic Signature

References

lists.apache.org /thread.html/r97d287c88881aa581f1b18cb01e2cbedc4e6eae85958491acb89b12e%40%3Cusers.openoffice.apache.org%3E
mailing-list, vendor-advisory
lists.apache.org /thread.html/raaab8a3b91f8d7b7ba14f873b8d0fd13952c823acc3385b7a374e754%40%3Cannounce.apache.org%3E
mailing-list

Sources

CVE List CVE-2021-41830
NVD CVE-2021-41830

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary