A vulnerability was identified in Firefox where XPath parsing could trigger undefined behavior due to missing null checks during attribute access. This could lead to out-of-bounds read access and potentially, memory corruption. This vulnerability affects Firefox < 138, Firefox ESR < 128.10, Thunderbird < 138, and Thunderbird ESR < 128.10.
CVE ID: CVE-2025-4087
CVSS Base Severity: MEDIUM
CVSS Base Score: 6.5
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Vendor: Mozilla
Product: Firefox, Firefox ESR, Thunderbird, Thunderbird ESR
EPSS Score: 0.08% (probability of being exploited)
EPSS Percentile: 23.46% (scored less or equal to compared to others)
EPSS Date: 2025-05-28 (when was this score calculated)