Description
SGLang through 0.5.20 in prefill/decode disaggregation mode fails to validate duplicate bootstrap_room fields in /generate requests with Mooncake KV transfer backend. Unauthenticated attackers can send concurrent requests with identical bootstrap_room values to crash scheduler processes or hang other users' requests until transfer timeout.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| sgl-project | sglang | ≤ 0.5.20 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | python-sglang | 0.5.20-2.1 | openSUSE-SU-2026:11947-1 |
Advisories 1
- openSUSE-SU-2026:11947-1 python313-sglang-0.5.20-2.1 on GA media SUSE / openSUSE Security Updates · Oct 2, 2026
References
- GitHub Issue #40125 issue-tracking
- https://github.com/sgl-project/sglang/blob/v0.5.20/python/sglang/srt/disaggregation/common/conn.py#L392-L393 technical-description
- https://github.com/sgl-project/sglang/blob/v0.5.20/python/sglang/srt/disaggregation/mooncake/conn.py#L2760-L2764 technical-description
- https://github.com/sgl-project/sglang/blob/v0.5.20/python/sglang/srt/disaggregation/decode.py#L942 technical-description
- https://github.com/sgl-project/sglang/blob/v0.5.20/python/sglang/srt/managers/io_struct.py#L281 technical-description
- https://github.com/sgl-project/sglang product
- VulnCheck Advisory: SGLang through 0.5.20 Denial of Service via Duplicate bootstrap_room third-party-advisory