{"id":"CVE-2026-73494","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-73494","generatedAt":"2026-10-28T11:20:59.076Z","title":"If a lenient or legacy proxy forwards the malformed bytes but interprets them differently, the disagreement can permit front-end authorization bypass, response-queue poisoning on pooled backend connections, or cache poisoning.","description":"blaze is a Scala library for building asynchronous pipelines, with a focus on network IO. Prior to 0.23.18 and from 1.0.0-M1 until 1.0.0-M42, five HTTP/1.1 conformance laxities in the hand-written Java parser under http/src/main/java/org/http4s/blaze/http/parser/ can cause blaze to derive a different request boundary than a stricter fronting intermediary. A default BlazeServerBuilder accepts invalid or valueless header field names that violate tchar syntax, obsolete folded field lines (obs-fold), unsupported Transfer-Encoding values, duplicate Content-Length fields, and requests containing both Transfer-Encoding and Content-Length. If a lenient or legacy proxy forwards the malformed bytes but interprets them differently, the disagreement can permit front-end authorization bypass, response-queue poisoning on pooled backend connections, or cache poisoning. Exploitation requires a pair of disagreeing parsers; no non-default blaze configuration is required. The affected checks are enforced in BodyAndHeaderParser and Http1ServerParser. This issue is fixed in versions 0.23.18 and 1.0.0-M42.","published":"2026-09-14T18:19:59.000Z","lastModified":"2026-09-30T17:51:56.000Z","status":"Deferred","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":7.4,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"},"cwe":["CWE-444"],"affected":[],"epss":{"score":0.00628,"percentile":0.49878,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.63%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/http4s/blaze/commit/3f7c022e306631b006dcb43a1d7f65c0d1966f17","source":"security-advisories@github.com"},{"url":"https://github.com/http4s/blaze/commit/4eec2007806aa9acfefb00ebb636ddc39a147a96","source":"security-advisories@github.com"},{"url":"https://github.com/http4s/blaze/commit/927b67753a78c13c4445dac9307f511f5c4878c3","source":"security-advisories@github.com"},{"url":"https://github.com/http4s/blaze/commit/a54bc9cd31758335c7f24e29763622fd03fcf734","source":"security-advisories@github.com"},{"url":"https://github.com/http4s/blaze/commit/c47d9675f87603f11b32a11d503626bdf9be5c7a","source":"security-advisories@github.com"},{"url":"https://github.com/http4s/blaze/commit/e871ebb1d27f50c98fd56988526ce42d0fee74d6","source":"security-advisories@github.com"},{"url":"https://github.com/http4s/blaze/releases/tag/v0.23.18","source":"security-advisories@github.com"},{"url":"https://github.com/http4s/blaze/releases/tag/v1.0.0-M42","source":"security-advisories@github.com"},{"url":"https://github.com/http4s/blaze/security/advisories/GHSA-mhvj-jhpq-885v","source":"security-advisories@github.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-73494","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}