layout/base/nsCSSFrameConstructor.cpp in the browser engine in Mozilla Firefox 3.0.x before 3.0.15 does not properly handle first-letter frames, which allows remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via unspecified vectors.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.174
EPSS Ranking 94.9%