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Fencer Vulns
high 7.5

CVE-2021-25636 json

Incorrect trust validation of signature with ambiguous KeyInfo children

published 2022-02-22 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-12532

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 61%
public exploits
0
none known

Summary

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 contain both "X509Data" and "KeyValue" children of the "KeyInfo" tag, which when opened caused LibreOffice to verify using the "KeyValue" but to report verification with the unrelated "X509Data" value. This issue affects: The Document Foundation LibreOffice 7.2 versions prior to 7.2.5.

Patch / fix

  • The Document Foundation LibreOffice 7.2.5
  • libreoffice Debian 14, Debian 13, Debian 12 1:7.3.0-1

debian advisories DEBIAN-CVE-2021-25636

  • libreoffice Ubuntu 18.04 LTS 1:6.0.7-0ubuntu0.18.04.11
  • libreoffice Ubuntu 20.04 LTS 1:6.4.7-0ubuntu0.20.04.4

ubuntu advisories UBUNTU-CVE-2021-25636

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libreoffice RHEL 8 1:6.4.7.2-11.el8
  • autocorr-af RHEL 8 1:6.4.7.2-11.el8
  • autocorr-bg RHEL 8 1:6.4.7.2-11.el8
  • autocorr-ca RHEL 8 1:6.4.7.2-11.el8
  • autocorr-cs RHEL 8 1:6.4.7.2-11.el8
  • autocorr-da RHEL 8 1:6.4.7.2-11.el8
  • autocorr-de RHEL 8 1:6.4.7.2-11.el8
  • autocorr-en RHEL 8 1:6.4.7.2-11.el8

red hat advisories RHSA-2022:7461

  • libreoffice SLE Workstation Extension 12 SP5, SLE Software Development Kit 12 SP5 7.2.5.1-48.19.4
  • libreoffice SLE Workstation Extension 15 SP3, SLE Module for Package Hub 15 SP3 7.2.5.1-150300.14.22.18.3

suse advisories SUSE-SU-2022:1093-1SUSE-SU-2022:0886-1

  • libreoffice openSUSE Leap 15.3 7.2.5.1-150300.14.22.18.3

opensuse advisories openSUSE-SU-2022:0886-1

  • autocorr-af AlmaLinux 8 1:6.4.7.2-11.el8.alma
  • autocorr-bg AlmaLinux 8 1:6.4.7.2-11.el8.alma
  • autocorr-ca AlmaLinux 8 1:6.4.7.2-11.el8.alma
  • autocorr-cs AlmaLinux 8 1:6.4.7.2-11.el8.alma
  • autocorr-da AlmaLinux 8 1:6.4.7.2-11.el8.alma
  • autocorr-de AlmaLinux 8 1:6.4.7.2-11.el8.alma
  • autocorr-en AlmaLinux 8 1:6.4.7.2-11.el8.alma
  • autocorr-es AlmaLinux 8 1:6.4.7.2-11.el8.alma

almalinux advisories ALSA-2022:7461

  • libreoffice Rocky Linux 8 1:6.4.7.2-11.el8

rocky linux advisories RLSA-2022:7461

  • libreoffice Alpine 3.15 7.2.7.2-r0
  • libreoffice Alpine 3.24, Alpine 3.23, Alpine 3.22 +6 more 7.2.5.2-r0

alpine advisories ALPINE-CVE-2021-25636

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-2021-25636 updated cvss 6.2

libreoffice: Incorrect trust validation of signature with ambiguous KeyInfo children

  • 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 9 autocorr-af, autocorr-bg, autocorr-ca, autocorr-cs, autocorr-da, autocorr-de, +101 more
    affected: no fix available
  • Red Hat CodeReady Linux Builder (v. 8) libreoffice-sdk 6.4.7.2-11.el8 Red Hat Enterprise Linux AppStream (v. 8) autocorr-af 6.4.7.2-11.el8, autocorr-bg 6.4.7.2-11.el8, autocorr-ca 6.4.7.2-11.el8, autocorr-cs 6.4.7.2-11.el8, autocorr-da 6.4.7.2-11.el8, autocorr-de 6.4.7.2-11.el8, +95 more
    fixed: vendor fix RHSA-2022:7461

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

Exploit prediction

0.95% chance of exploitation in the next 30 days, higher than 61% 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

  • The Document Foundation LibreOffice

Classification

Weakness
  • CWE-347 Improper Verification of Cryptographic Signature
  • 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.