CVE-2026-109718: Use-after-free in the XML component

Published Oct 13, 2026
·
Updated

Use-after-free in the XML component. This vulnerability was fixed in Firefox 158, Firefox ESR 115.43, and Firefox ESR 153.5.

Other sources

Use-after-free in the XML component. This vulnerability was fixed in Firefox 158, Firefox ESR 115.43, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

— NVD

Affected Software

5 affected componentsFixes available
Mozilla Firefox<158
158
Mozilla Firefox ESR<115.43
115.43
Mozilla Firefox ESR<153.5
153.5
Mozilla Thunderbird<153.5
153.5
Mozilla Thunderbird<158
158

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 158
  2. Upgrade

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

    Fixed in 115.43
  3. Upgrade

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

    Fixed in 153.5
  4. Upgrade

    Upgrade Firefox to a version that resolves this vulnerability.

    Fixed in 158
  5. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 115.43
  6. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 153.5
  7. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 158
  8. Upgrade

    Upgrade Thunderbird 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
CVE Published
via MITRE·12:29 PM
Data Sourced
via MITRE·12:29 PM
Description
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 issue was fixed in Firefox 158, Firefox ESR 115.43, and Firefox ESR 153.5.

2

Does exploitation require a local account or prior authentication?

No. The CVSS vector indicates network-based exploitation with no privileges required, although user interaction is required.

3

What is the likely security impact if exploitation succeeds?

The CVSS vector rates confidentiality and integrity impact as low, with no availability impact.

Company

Resources

Contact

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