Evidence used
- No CISA KEV confirmation is currently recorded.
- EPSS is 0.32% for the current model date.
BlackTreeCVE IntelligenceMozilla · Firefox
Critical technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 2 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
Verified remediation exists for at least one product or source, but 2 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.
BlackTree has verified remediation for at least one product or source, but the relevant distribution still reports no fixed package for 2 affected package states shown here. Treat those rows as affected with no fix until that distribution publishes a fixed version.
A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.
| Distribution release | Source package | Vendor state | Fixed version | Evidence |
|---|---|---|---|---|
| Debian trixietrixie · source | firefox-esr | Vendor fix publishedDebian records a fixed source-package version for this release. | 153.4.0esr-1~deb13u1 | Debian Security Tracker ↗Source updated 4 Oct 2026 |
| Debian trixietrixie · source | thunderbird | Not affectedDebian marks this release not affected (fixed-version marker 0). | Not published in this feed | Debian Security Tracker ↗Source updated 4 Oct 2026 |
| Debian bookwormbookworm · source | firefox-esr | Vendor fix publishedDebian records a fixed source-package version for this release. | 153.4.0esr-1~deb12u1 | Debian Security Tracker ↗Source updated 4 Oct 2026 |
| Debian bookwormbookworm · source | thunderbird | Not affectedDebian marks this release not affected (fixed-version marker 0). | Not published in this feed | Debian Security Tracker ↗Source updated 4 Oct 2026 |
| Debian forkyforky · source | firefox-esr | Affected, no fix publishedDebian currently tracks this release as open. | Not published in this feed | Debian Security Tracker ↗Source updated 4 Oct 2026 |
| Debian forkyforky · source | thunderbird | Affected, no fix publishedDebian currently tracks this release as open. | Not published in this feed | Debian Security Tracker ↗Source updated 4 Oct 2026 |
| Debian sidsid · source | firefox | Vendor fix publishedDebian records a fixed source-package version for this release. | 157.0-1 | Debian Security Tracker ↗Source updated 4 Oct 2026 |
| Debian sidsid · source | firefox-esr | Vendor fix publishedDebian records a fixed source-package version for this release. | 153.4.0esr-1 | Debian Security Tracker ↗Source updated 4 Oct 2026 |
| Debian sidsid · source | thunderbird | Vendor fix publishedDebian records a fixed source-package version for this release. | 1:153.4.0esr-1 | Debian Security Tracker ↗Source updated 4 Oct 2026 |
| Ubuntu 24.04 LTSnoble · standard archive | mozjs102 | Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing. | Not published in this feed | Canonical Ubuntu Security ↗Source updated 2 Oct 2026 |
| Ubuntu 24.04 LTSnoble · standard archive | mozjs115 | Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing. | Not published in this feed | Canonical Ubuntu Security ↗Source updated 2 Oct 2026 |
Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.
The vendor explicitly identifies these products as affected by this CVE.
Critical technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 2 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.
Fix availability varies by productSandbox escape in the XUL component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157.
Sandbox escape in the XUL component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157.
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
Sandbox escape in the XUL component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157.
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
An attacker operating through a network path may attempt exploitation without authentication after a user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.
CWE-20: Improper Input Validation. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:HCommon Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
Operational remediation based on structured source evidence.
Linked articles are downloaded and versioned as source evidence. A CVE mention or approved update relationship does not, by itself, verify a fix for every product branch.
Published 29 Sept 2026 · Last source change 1 Oct 2026, 15:29 UTC · CWE-20 · Improper Input Validation
Core structured fields are present and their contributing authorities are shown above.