Description

Integer overflow in the Layout: Text and Fonts component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

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References

Other References

https://bugzilla.mozilla.org/show_bug.cgi?id=2074171 https://www.mozilla.org/security/advisories/mfsa2026-106/ https://www.mozilla.org/security/advisories/mfsa2026-108/ https://www.mozilla.org/security/advisories/mfsa2026-109/ https://www.mozilla.org/security/advisories/mfsa2026-110/

Frequently Asked Questions

What is CVE-2026-109723? +

Integer overflow in the Layout: Text and Fonts component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

How do I check if I'm vulnerable to CVE-2026-109723? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.