Hono before 4.12.7 allows proto key in parseBody with dot option enabled, permitting specially crafted form field names to create objects with proto properties. When parsed results are merged into regular JavaScript objects using unsafe merge patterns, attackers can exploit this to achieve prototype pollution and modify object behavior.
Exploitability
AV:NAC:HAT:PPR:NUI:NVulnerable System
VC:LVI:LVA:NSubsequent System
SC:NSI:NSA:N6.3/CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:NInput Validation