{"id":"JLSEC-2026-515","details":"There's a flaw in the zeromq server in versions before 4.3.3 in src/decoder_allocators.hpp. The decoder static allocator could have its sized changed, but the buffer would remain the same as it is a static buffer. A remote, unauthenticated attacker who sends a crafted request to the zeromq server could trigger a buffer overflow WRITE of arbitrary data if CURVE/ZAP authentication is not enabled. The greatest impact of this flaw is to application availability, data integrity, and confidentiality.","modified":"2026-05-20T04:15:03.610095157Z","published":"2026-05-20T04:02:19.667Z","upstream":["CVE-2021-20235"],"database_specific":{"sources":[{"modified":"2024-11-21T05:46:11.220Z","published":"2021-04-01T14:15:13.217Z","imported":"2026-05-20T01:02:00.969Z","html_url":"https://nvd.nist.gov/vuln/detail/CVE-2021-20235","url":"https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2021-20235","id":"CVE-2021-20235","database_specific":{"status":"Modified"}}],"license":"CC-BY-4.0"},"references":[{"type":"WEB","url":"https://bugzilla.redhat.com/show_bug.cgi?id=1921983"},{"type":"WEB","url":"https://bugzilla.redhat.com/show_bug.cgi?id=1921983"},{"type":"WEB","url":"https://github.com/zeromq/libzmq/security/advisories/GHSA-fc3w-qxf5-7hp6"},{"type":"WEB","url":"https://github.com/zeromq/libzmq/security/advisories/GHSA-fc3w-qxf5-7hp6"}],"affected":[{"package":{"name":"ZeroMQ_jll","ecosystem":"Julia","purl":"pkg:julia/ZeroMQ_jll?uuid=8f1865be-045e-5c20-9c9f-bfbfb0764568"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"4.3.4+0"}]}],"database_specific":{"source":"https://github.com/JuliaLang/SecurityAdvisories.jl/tree/generated/osv/2026/JLSEC-2026-515.json"}}],"schema_version":"1.7.5"}