{"id":"EEF-CVE-2026-77972","summary":"safeurl validated address is not bound to the request, allowing DNS rebinding","details":"## Summary\n\nTime-of-check Time-of-use (TOCTOU) Race Condition in Slab safeurl allows an attacker who controls a hostname's DNS responses to reach internal network destinations that validation rejected.\n\nValidation returns a verdict and not the address it approved, so the HTTP clients the library ships receive the original hostname and resolve it a second time when the request is made. An attacker who controls the authoritative DNS for a name can answer the first lookup with a permitted address and the second with a blocked one, and the request then reaches a destination validation never approved. The same window opens without an attacker whenever a name legitimately resolves to different addresses across lookups, such as short record lifetimes or rotation between several addresses.\n\nThis issue affects safeurl: from 0.1.0 onward.","aliases":["CVE-2026-77972"],"modified":"2026-09-15T15:45:03.321931831Z","published":"2026-09-15T15:37:49.948Z","database_specific":{"capec_ids":["CAPEC-664"],"cpe_ids":["cpe:2.3:a:slab:safeurl:*:*:*:*:*:*:*:*"],"cwe_ids":["CWE-367"]},"references":[{"type":"WEB","url":"https://cna.erlef.org/cves/CVE-2026-77972.html"},{"type":"WEB","url":"https://github.com/slab/safeurl-elixir/commit/feabbd0a13f83028ab24b71710526e9da9841f70"},{"type":"PACKAGE","url":"https://hex.pm/packages/safeurl"}],"affected":[{"package":{"name":"safeurl","ecosystem":"Hex","purl":"pkg:hex/safeurl"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0.1.0"}]}],"versions":["0.1.0","0.2.0","0.3.0","0.3.1","1.0.0"],"database_specific":{"source":"https://cna.erlef.org/osv/EEF-CVE-2026-77972.json"}},{"ranges":[{"type":"GIT","repo":"https://github.com/slab/safeurl-elixir","events":[{"introduced":"feabbd0a13f83028ab24b71710526e9da9841f70"}]}],"versions":["v1.0.0","v0.3.1","v0.3.0","v0.2.0","v0.1.0"],"database_specific":{"source":"https://cna.erlef.org/osv/EEF-CVE-2026-77972.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N"}],"credits":[{"name":"Jonatan Männchen / EEF","type":"REPORTER"},{"name":"Jonatan Männchen / EEF","type":"COORDINATOR"}]}