CyberSecBulletin
CVE-2022-26305NVD status: Modified

LibreOffice: Improper Certificate Validation

Published Updated By the CyberSecBulletin desk

CVE-2022-26305 is a high-severity improper certificate validation vulnerability in LibreOffice from The Document Foundation, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists versions 7.2.7, 7.3.1 as the first without the flaw, so updating LibreOffice to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 1.24% chance of exploitation within 30 days, higher than 70% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update LibreOffice to 7.2.7 or 7.3.1, whichever matches your release line, or a later version.
  2. Read the advisory on libreoffice.org for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
  4. Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.

Affected products and versions

VendorProductAffected versionsFixed in
The Document FoundationLibreOffice7.2 up to, but not including, 7.2.7; 7.3 up to, but not including, 7.3.17.2.7, 7.3.1

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
HighSuccess depends on conditions outside the attacker's control.
Privileges required
NoneNo account or login is needed.
User interaction
RequiredA user must take an action such as opening a file or link.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by NVD.

Official description

An Improper Certificate Validation vulnerability in LibreOffice existed where determining if a macro was signed by a trusted author was done by only matching the serial number and issuer string of the used certificate with that of a trusted certificate. This is not sufficient to verify that the macro was actually signed with the certificate. An adversary could therefore create an arbitrary certificate with a serial number and an issuer string identical to a trusted certificate which LibreOffice would present as belonging to the trusted author, potentially leading to the user to execute arbitrary code contained in macros improperly trusted. This issue affects: The Document Foundation LibreOffice 7.2 versions prior to 7.2.7; 7.3 versions prior to 7.3.1.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Certificate Validation

The product does not validate, or incorrectly validates, a certificate.

How developers prevent this class of flaw

  • Certificates should be carefully managed and checked to assure that data are encrypted with the intended owner's public key.
  • If certificate pinning is being used, ensure that all relevant properties of the certificate are fully validated before the certificate is pinned, including the hostname.

More Improper Certificate Validation vulnerabilities (CWE-295)

Timeline

  1. CVE record published.
  2. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in LibreOffice

All LibreOffice vulnerabilities

Recent Improper Certificate Validation vulnerabilities

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