CVE-2026-100778

Sandbox escape due to use-after-free in the DOM: Core & HTML component

cve-program · severity unknownCVSS unknownCheck source for fixed versionsKEV status unknown

Original advisory

Historical advisory recorded 23 Oct 2026 15:48:27 UTC. Read the latest advisory.

cve-program · CVE-2026-100778

Published

Sandbox escape due to use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

Read the publisher's advisory

Affected versions, risk and source history

cve-program · CVE-2026-100778

Published

Firefox

Vendor product

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "product": "Firefox",
                    "vendor": "Mozilla",
                    "versions": [
                        {
                            "status": "unaffected",
                            "version": "115.42",
                            "lessThanOrEqual": "115.*",
                            "versionType": "rpm"
                        },
                        {
                            "status": "unaffected",
                            "version": "140.17",
                            "lessThanOrEqual": "140.*",
                            "versionType": "rpm"
                        },
                        {
                            "status": "unaffected",
                            "version": "153.4",
                            "lessThanOrEqual": "153.*",
                            "versionType": "rpm"
                        },
                        {
                            "status": "unaffected",
                            "version": "157",
                            "lessThanOrEqual": "*",
                            "versionType": "rpm"
                        }
                    ]
                }

Thunderbird

Vendor product

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "product": "Thunderbird",
                    "vendor": "Mozilla",
                    "versions": [
                        {
                            "status": "unaffected",
                            "version": "140.17",
                            "lessThanOrEqual": "140.*",
                            "versionType": "rpm"
                        },
                        {
                            "status": "unaffected",
                            "version": "153.4",
                            "lessThanOrEqual": "153.*",
                            "versionType": "rpm"
                        },
                        {
                            "status": "unaffected",
                            "version": "157",
                            "lessThanOrEqual": "*",
                            "versionType": "rpm"
                        }
                    ]
                }

Original source record · Cite this exact observation · Complete original publisher JSON