Description
Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.
Published: 2026-06-16
Score: 5.4 Medium
EPSS: < 1% Very Low
KEV: No
Impact: Moderate memory safety flaw leading to potential data disclosure or application crash
Action: Apply Patch
AI Analysis

Impact

Prior to version 152, Mozilla Thunderbird was vulnerable to a memory safety flaw that could lead to out‑of‑bounds read, use‑after‑free, or type confusion, as listed by the CWEs (CWE-125, CWE-787, CWE-416, CWE-843). This flaw, now fixed in Thunderbird 152 and Thunderbird ESR 140.12, could allow an attacker to read sensitive data, corrupt application state, or cause a crash, impacting confidentiality and availability.

Affected Systems

The flaw affects Mozilla Firefox and Mozilla Thunderbird versions prior to 152 (or Firefox ESR 140.12 and Thunderbird ESR 140.12). The bug was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.

Risk and Exploitability

The CVSS score of 5.4 indicates a moderate severity. The EPSS score of <1% shows a very low probability of exploitation, and the vulnerability is not listed in the CISA KEV catalog. It is inferred that exploitation would likely require an attacker to deliver malicious content to the application, such as a crafted email or attachment, or to exploit local privileges during processing.

Generated by OpenCVE AI on October 23, 2026 at 01:01 UTC.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Update to the latest Mozilla Firefox release (152 or newer) or apply the ESR 140.12 update.
  • Update to the latest Mozilla Thunderbird release (152 or newer) or apply the ESR 140.12 update.
  • If a patch cannot be applied immediately, avoid using the compromised versions and disable any untrusted extensions that may interact with email content until the update is installed.

Generated by OpenCVE AI on October 23, 2026 at 01:01 UTC.

Tracking

Sign in to view the affected projects.

Advisories
Source ID Title
Debian DLA Debian DLA DLA-4635-1 firefox-esr security update
Debian DLA Debian DLA DLA-4636-1 thunderbird security update
Debian DSA Debian DSA DSA-6350-1 firefox-esr security update
Debian DSA Debian DSA DSA-6351-1 thunderbird security update
References
Link Providers
https://access.redhat.com/errata/RHSA-2026:27717 cve-icon
https://access.redhat.com/errata/RHSA-2026:27733 cve-icon
https://access.redhat.com/errata/RHSA-2026:27734 cve-icon
https://access.redhat.com/errata/RHSA-2026:29940 cve-icon
https://access.redhat.com/errata/RHSA-2026:30846 cve-icon
https://access.redhat.com/errata/RHSA-2026:33445 cve-icon
https://access.redhat.com/errata/RHSA-2026:36100 cve-icon
https://access.redhat.com/errata/RHSA-2026:36101 cve-icon
https://access.redhat.com/errata/RHSA-2026:36102 cve-icon
https://access.redhat.com/errata/RHSA-2026:36103 cve-icon
https://access.redhat.com/errata/RHSA-2026:37210 cve-icon
https://access.redhat.com/errata/RHSA-2026:37391 cve-icon
https://access.redhat.com/errata/RHSA-2026:38506 cve-icon
https://access.redhat.com/errata/RHSA-2026:38750 cve-icon
https://access.redhat.com/errata/RHSA-2026:38751 cve-icon
https://access.redhat.com/errata/RHSA-2026:38753 cve-icon
https://access.redhat.com/errata/RHSA-2026:39011 cve-icon
https://access.redhat.com/errata/RHSA-2026:39141 cve-icon
https://access.redhat.com/errata/RHSA-2026:39142 cve-icon
https://access.redhat.com/errata/RHSA-2026:39428 cve-icon
https://access.redhat.com/errata/RHSA-2026:39706 cve-icon
https://access.redhat.com/security/cve/CVE-2026-12298 cve-icon
https://bugzilla.mozilla.org/show_bug.cgi?id=2041981 cve-icon cve-icon
https://bugzilla.redhat.com/show_bug.cgi?id=2489248 cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2026-12298 cve-icon
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-12298.json cve-icon
https://www.cve.org/CVERecord?id=CVE-2026-12298 cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-57/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-58/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-58/#CVE-2026-12298 cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-60/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-61/ cve-icon cve-icon
https://www.mozilla.org/security/advisories/mfsa2026-61/#CVE-2026-12298 cve-icon
History

Wed, 21 Oct 2026 14:00:00 +0000

Type Values Removed Values Added
Description Memory safety bug fixed in Firefox 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12. Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.
Title Memory safety bug fixed in Firefox 152 Memory safety bug fixed in Thunderbird 152

Thu, 18 Jun 2026 18:45:00 +0000

Type Values Removed Values Added
Description Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12. Memory safety bug fixed in Firefox 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.
Title Memory safety bug fixed in Thunderbird 152 Memory safety bug fixed in Firefox 152

Thu, 18 Jun 2026 16:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-843
References
Metrics threat_severity

None

 threat_severity

Important

Tue, 16 Jun 2026 20:45:00 +0000

Type Values Removed Values Added
First Time appeared Mozilla thunderbird
CPEs cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:*
Vendors & Products Mozilla thunderbird

Tue, 16 Jun 2026 16:45:00 +0000

Type Values Removed Values Added
Description Memory safety bug fixed in Firefox 152. This vulnerability was fixed in Firefox 152 and Firefox ESR 140.12. Memory safety bug fixed in Thunderbird 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.
Title Memory safety bug fixed in Firefox 152 Memory safety bug fixed in Thunderbird 152
References

Tue, 16 Jun 2026 16:15:00 +0000

Type Values Removed Values Added
First Time appeared Mozilla
Mozilla firefox
Vendors & Products Mozilla
Mozilla firefox

Tue, 16 Jun 2026 15:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-125
CWE-416
CWE-787
Metrics cvssV3_1

{'score': 5.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Tue, 16 Jun 2026 13:15:00 +0000

Type Values Removed Values Added
Description Memory safety bug fixed in Firefox 152. This vulnerability was fixed in Firefox 152 and Firefox ESR 140.12.
Title Memory safety bug fixed in Firefox 152
References

Subscriptions

Mozilla Firefox Thunderbird
cve-icon MITRE

Status: PUBLISHED

Assigner: mozilla

Published:

Updated: 2026-10-21T13:49:59.783Z

Reserved: 2026-06-15T15:08:09.561Z

Link: CVE-2026-12298

cve-icon Vulnrichment

Updated: 2026-07-15T11:48:26.536Z

cve-icon NVD

Status : Modified

Published: 2026-06-16T13:16:30.040

Modified: 2026-10-26T13:10:00.140

Link: CVE-2026-12298

cve-icon Redhat

Severity : Important

Publid Date: 2026-06-16T11:52:31Z

Links: CVE-2026-12298 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-10-23T01:15:14Z

Weaknesses
  • CWE-125

    Out-of-bounds Read

  • CWE-416

    Use After Free

  • CWE-787

    Out-of-bounds Write

  • CWE-843

    Access of Resource Using Incompatible Type ('Type Confusion')