CVE-2025-10533 is an integer overflow vulnerability in the SVG component affecting Firefox and Thunderbird. It impacts Firefox versions prior to 143, Firefox ESR versions prior to 115.28 and 140.3, and Thunderbird versions prior to 143 and 140.3. The vulnerability is classified as moderate impact in ESR 115.28 but moderate to high impact in other versions due to memory safety concerns. Mozilla has released fixes in Firefox 143, Firefox ESR 115.28 and 140.3, and Thunderbird 143 and 140.3.