CVE-2021-29988
Mozilla: Memory corruption as a result of incorrect style treatment
Severity
ImportantRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · August 10, 2021
Updated · November 22, 2025
Description
Firefox incorrectly treated an inline list-item element as a block element, resulting in an out of bounds read or memory corruption, and a potentially exploitable crash. This vulnerability affects Thunderbird < 78.13, Thunderbird < 91, Firefox ESR < 78.13, and Firefox < 91.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.1 · 8.8CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CWE-119 · Improper Restriction of Operations within the Bounds of a Memory Buffer