{"id":"CVE-2026-93838","title":"SGLang versions through 0.5.20 contain an unbounded memory allocation vulnerability in handle_staging_req() that fails to validate chunk_idx from ZMQ STAGING_REQ frames in prefill/decode disaggregation deployments","summary":"SGLang versions through 0.5.20 contain an unbounded memory allocation vulnerability in handle_staging_req() that fails to validate chunk_idx from ZMQ STAGING_REQ frames in prefill/decode disaggregation deployments. Attackers with access …","severity":"medium","cvss":5.9,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-770"],"vendor":"sgl-project","product":"sglang","affected":["sglang <= 0.5.20"],"published":"2026-09-18","updated":"2026-09-22","sourceUpdated":"2026-09-22T20:43:58.793","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-93838","references":[{"url":"https://github.com/sgl-project/sglang","label":"disclosure@vulncheck.com"},{"url":"https://github.com/sgl-project/sglang/blob/v0.5.20/python/sglang/srt/disaggregation/common/conn.py#L1636-L1640","label":"disclosure@vulncheck.com"},{"url":"https://github.com/sgl-project/sglang/blob/v0.5.20/python/sglang/srt/disaggregation/common/staging_handler.py#L781","label":"disclosure@vulncheck.com"},{"url":"https://github.com/sgl-project/sglang/blob/v0.5.20/python/sglang/srt/disaggregation/common/staging_handler.py#L848-L860","label":"disclosure@vulncheck.com"},{"url":"https://github.com/sgl-project/sglang/issues/39764","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/sglang-through-0.5.20-unbounded-memory-allocation-via-staging-req-chunk-idx","label":"disclosure@vulncheck.com"},{"url":"https://github.com/sgl-project/sglang/issues/39764","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"tags":["nvd","cve.org","exploit-available"],"epss":0.00652,"epssPercentile":0.4902,"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"partial","timestamp":"2026-09-18T20:09:38.130553Z"},"ingestedAt":"2026-09-18T19:49:30.603Z","slug":"CVE-2026-93838","body":"## Overview\n\nSGLang versions through 0.5.20 contain an unbounded memory allocation vulnerability in handle_staging_req() that fails to validate chunk_idx from ZMQ STAGING_REQ frames in prefill/decode disaggregation deployments. Attackers with access to the decode engine's internal ZMQ rank port can send a frame with an extremely large chunk_idx value, causing the scheduler to allocate memory until the system runs out and terminates the process.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":45,"depthScoreParts":{"impact":32.5,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":207510,"id":"CVE-2026-93838","ts":1789764776033,"field":"exploit_available","old":"false","new":"true"}]}