CVE-2026-109742: Information disclosure in the PDF Viewer component

Published Oct 13, 2026
·
Updated

Information disclosure in the PDF Viewer component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

Other sources

Information disclosure in the PDF Viewer component. This vulnerability was fixed in Firefox 158 and Firefox ESR 153.5.

— Red Hat

Affected Software

17 affected componentsFixes available
Mozilla Thunderbird<153.5
153.5
ubuntu/mozjs52*
ubuntu/mozjs38*
ubuntu/mozjs68*
ubuntu/mozjs52*
ubuntu/mozjs102*
ubuntu/mozjs78*
ubuntu/mozjs91*
ubuntu/thunderbird*
ubuntu/mozjs102*
ubuntu/mozjs115*
Mozilla Firefox<158
158
Mozilla Firefox ESR<153.5
153.5
Mozilla Thunderbird<158
158
debian/firefox
159.0-1
debian/firefox-esr<=140.12.0esr-1~deb12u1, <=140.15.0esr-1~deb13u1
153.6.0esr-1~deb12u2153.6.0esr-1~deb13u1153.5.1esr-1153.6.0esr-1
debian/thunderbird<=1:140.12.0esr-1~deb12u1, <=1:140.12.0esr-1~deb13u1
1:153.6.0esr-1~deb12u21:153.6.0esr-1~deb13u11:153.5.0esr-11:153.6.0esr-1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 153.5
  2. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 158
  3. Upgrade

    Upgrade debian/firefox to a version that resolves this vulnerability.

    Fixed in 159.0-1
  4. Upgrade

    Upgrade debian/firefox-esr to a version that resolves this vulnerability.

    Fixed in 153.6.0esr-1~deb12u2Fixed in 153.6.0esr-1~deb13u1Fixed in 153.5.1esr-1Fixed in 153.6.0esr-1
  5. Upgrade

    Upgrade debian/thunderbird to a version that resolves this vulnerability.

    Fixed in 1:153.6.0esr-1~deb12u2Fixed in 1:153.6.0esr-1~deb13u1Fixed in 1:153.5.0esr-1Fixed in 1:153.6.0esr-1
  6. Upgrade

    Upgrade Firefox to a version that resolves this vulnerability.

    Fixed in 158
  7. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 153.5
  8. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 158
  9. Upgrade

    Upgrade Thunderbird ESR to a version that resolves this vulnerability.

    Fixed in 153.5

Event History

Oct 13, 2026
CVE Published
via Mozilla·12:00 AM
Data Sourced
via Mozilla·12:00 AM
DescriptionSeverityAffected Software
Data Sourced
via Ubuntu·12:00 AM
RemedyDescriptionSeverityAffected Software
CVE Published
via MITRE·12:29 PM
Data Sourced
via MITRE·12:29 PM
Description
Data Sourced
via Red Hat·12:54 PM
DescriptionSeverityAffected Software
Data Sourced
via OSV·01:17 PM
DescriptionSeverityAffected Software
Data Sourced
via NVD·01:17 PM
DescriptionSeverityWeakness

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

Frequently Asked Questions

1

Which Firefox releases contain the fix?

The vulnerability was fixed in Firefox 158 and Firefox ESR 153.5.

2

Does exploitation require a user action?

Yes. The CVSS vector indicates user interaction is required, and it also indicates the attacker does not need prior privileges.

3

What is the expected impact if exploited?

The reported impact is limited to confidentiality: an attacker may disclose information. No integrity or availability impact is indicated by the CVSS vector.

Company

Resources

Contact

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