Jailbreak transferability is the ability of an adversarial prompt or attack designed to bypass the safety guardrails of one large language model to successfully elicit prohibited responses from a different, previously untargeted model without modification. In artificial intelligence security and red teaming, this phenomenon occurs when an exploit engineered or optimized against an accessible source system, such as an open-weight model where gradients are accessible, generalizes to breach the alignment filters of black-box or proprietary models. Jailbreak transferability represents a significant challenge for safety evaluation because it allows attackers to undermine guardrails across diverse model families by exploiting shared semantic representations and common alignment vulnerabilities rather than designing unique exploits for each system.