Mitigation bypass in Mozilla DOM Security component
CVE-2026-12315 is a mitigation bypass vulnerability in Mozilla's DOM Security component affecting Firefox and Thunderbird. The provided advisory text identifies the issue only as a "Mitigation bypass in the DOM: Security component" and does not disclose the specific vulnerable function, code path, or triggering conditions. The flaw allows an attacker to bypass an intended browser-side security mitigation within the DOM security subsystem, weakening protections that are meant to constrain unsafe or unauthorized behavior. Mozilla reports this issue as fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird ESR 140.12.
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Impact, mitigation & remediation
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
Impact
What an attacker gets, and what they’ve been doing with it.
Mitigation
If you can’t patch tonight, do this now.
Remediation
Patch, then assume compromise.
Exploits
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
Affected products & vendors
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
7 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.
No news coverage yet. Advisories and community discussion only.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.