Ports that were written as an integer overflow above the bounds of a 16-bit integer could have bypassed port blocking restrictions when used in the Alt-Svc header. This vulnerability affects Firefox ESR < 78.10, Thunderbird < 78.10, and Firefox < 88.
The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.
| Link | Tags |
|---|---|
| https://www.mozilla.org/security/advisories/mfsa2021-14/ | release notes vendor advisory |
| https://www.mozilla.org/security/advisories/mfsa2021-16/ | release notes vendor advisory |
| https://www.mozilla.org/security/advisories/mfsa2021-15/ | release notes vendor advisory |
| https://bugzilla.mozilla.org/show_bug.cgi?id=1698503 | permissions required vendor advisory |