CVE-2026-109782
HIGHDescription
Mitigation bypass in the File Handling component. This vulnerability was fixed in Firefox ESR 153.5 and Thunderbird 153.5.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H
Exploit Intelligence
Low risk: more likely to be exploited than 20% of all known CVEs.
References
Related Vulnerabilities
Other CWE-693 (Protection Mechanism Failure) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2024-21412 | High | 8.1 | 99% | KEV + Ransom | Fix |
| CVE-2013-2465 | Critical | 9.8 | 99% | KEV + Ransom | - |
| CVE-2019-1003030 | Critical | 9.9 | 97% | KEV | - |
| CVE-2013-0431 | Low | 3.7 | 90% | KEV + Ransom | - |
| CVE-2025-40536 | High | 8.1 | 74% | KEV | Fix |
| CVE-2026-32202 | Medium | 4.3 | 71% | KEV | Fix |
Common questions
How do I fix CVE-2026-109782?
Upgrade firefox-esr on debian 12 to 153.5.0esr-1~deb12u1 or later.
Is CVE-2026-109782 being actively exploited?
Not that we know of. CVE-2026-109782 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.27% is the estimated probability that it will be exploited in the next 30 days. That is higher than 20% of all scored CVEs.
How severe is CVE-2026-109782?
CVE-2026-109782 has a CVSS v3 base score of 8.3, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-109782 affect?
Published advisories record a fix for firefox-esr (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2026-109782
Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-10-26.