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Fencer Vulns
medium 5.5

CVE-2021-25635 json

Content Manipulation with Certificate Validation Attack

published 2025-03-21 19 mo ago modified 2026-06-17 4 mo ago also EUVD-2021-12531

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 3%
public exploits
0
none known

Summary

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.

Patch / fix

  • The Document Foundation LibreOffice 7.0.5, 7.1.1
  • libreoffice RHEL 8 1:6.4.7.2-10.el8
  • autocorr-af RHEL 8 1:6.4.7.2-10.el8
  • autocorr-bg RHEL 8 1:6.4.7.2-10.el8
  • autocorr-ca RHEL 8 1:6.4.7.2-10.el8
  • autocorr-cs RHEL 8 1:6.4.7.2-10.el8
  • autocorr-da RHEL 8 1:6.4.7.2-10.el8
  • autocorr-de RHEL 8 1:6.4.7.2-10.el8
  • autocorr-en RHEL 8 1:6.4.7.2-10.el8

red hat advisories RHSA-2022:1766

  • autocorr-af AlmaLinux 8 1:6.4.7.2-10.el8.alma
  • autocorr-bg AlmaLinux 8 1:6.4.7.2-10.el8.alma
  • autocorr-ca AlmaLinux 8 1:6.4.7.2-10.el8.alma
  • autocorr-cs AlmaLinux 8 1:6.4.7.2-10.el8.alma
  • autocorr-da AlmaLinux 8 1:6.4.7.2-10.el8.alma
  • autocorr-de AlmaLinux 8 1:6.4.7.2-10.el8.alma
  • autocorr-en AlmaLinux 8 1:6.4.7.2-10.el8.alma
  • autocorr-es AlmaLinux 8 1:6.4.7.2-10.el8.alma

almalinux advisories ALSA-2022:1766

  • libreoffice Rocky Linux 8 1:6.4.7.2-10.el8

rocky linux advisories RLSA-2022:1766

  • libreoffice Alpine 3.24, Alpine 3.23, Alpine 3.22 +7 more 7.2.2.2-r0

alpine advisories ALPINE-CVE-2021-25635

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-25635 updated cvss 6.3

libreoffice: Content Manipulation with Certificate Validation Attack

  • Red Hat Enterprise Linux 6 autocorr-af, autocorr-bg, autocorr-ca, autocorr-cs, autocorr-da, autocorr-de, +60 more Red Hat Enterprise Linux 7 autocorr-af, autocorr-bg, autocorr-ca, autocorr-cs, autocorr-da, autocorr-de, +105 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 autocorr-af, autocorr-bg, autocorr-ca, autocorr-cs, autocorr-da, autocorr-de, +98 more
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux AppStream (v. 8) autocorr-af 6.4.7.2-10.el8, autocorr-bg 6.4.7.2-10.el8, autocorr-ca 6.4.7.2-10.el8, autocorr-cs 6.4.7.2-10.el8, autocorr-da 6.4.7.2-10.el8, autocorr-de 6.4.7.2-10.el8, +95 more Red Hat Enterprise Linux CRB (v. 8) libreoffice-sdk 6.4.7.2-10.el8
    fixed: vendor fix RHSA-2022:1766
  • Red Hat Enterprise Linux 9 autocorr-af, autocorr-bg, autocorr-ca, autocorr-cs, autocorr-da, autocorr-de, +101 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
19 mo ago

Exploit prediction

0.14% chance of exploitation in the next 30 days, higher than 3% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 5.2 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
CNA 4.0 5.2 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 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

Affected products

  • The Document Foundation LibreOffice

Classification

Weakness
  • CWE-295 Improper Certificate Validation

References

Sources

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.