SGLang through 0.5.19 in prefill/decode disaggregation mode contains an unauthenticated PUT /route endpoint on the prefill bootstrap service that allows attackers to poison the KV transfer routing table. Attackers can supply arbitrary rank_ip and rank_port values to redirect decode workers to attacker-controlled endpoints, causing denial of service or disclosure of KV transfer metadata including session identifiers and tensor-parallel topology parameters.
Published: 2026-09-17
Updated: 2026-09-22
Base Score: 9
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:C
Severity: High
Base Score: 8.6
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
Severity: High
Base Score: 8.8
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N
Severity: High
EPSS: 0.00332