{"cve":"CVE-2026-73494","nvd":{"published":"2026-09-14T18:19:58.857","modified":"2026-09-30T17:51:56.193","status":"Deferred","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N","score":7.4},"cwes":["CWE-444"],"references":["https://github.com/http4s/blaze/commit/3f7c022e306631b006dcb43a1d7f65c0d1966f17","https://github.com/http4s/blaze/commit/4eec2007806aa9acfefb00ebb636ddc39a147a96","https://github.com/http4s/blaze/commit/927b67753a78c13c4445dac9307f511f5c4878c3","https://github.com/http4s/blaze/commit/a54bc9cd31758335c7f24e29763622fd03fcf734","https://github.com/http4s/blaze/commit/c47d9675f87603f11b32a11d503626bdf9be5c7a"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:53:43.293028046+00:00"},"epss":{"cve":"CVE-2026-73494","score":0.00628,"percentile":0.49787,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-mhvj-jhpq-885v","url":"https://osv.dev/vulnerability/GHSA-mhvj-jhpq-885v","summary":"blaze: Multiple HTTP/1.1 request-smuggling primitives in blaze's Java wire parser","modified":"2026-08-12T21:25:59.355788Z","packages":[{"ecosystem":"Maven","name":"org.http4s:http4s-blaze-server_2.13","purl":"pkg:maven/org.http4s/http4s-blaze-server_2.13","ranges":["<0.23.18"],"fixed":["0.23.18"]},{"ecosystem":"Maven","name":"org.http4s:blaze-http_2.13","purl":"pkg:maven/org.http4s/blaze-http_2.13","ranges":["<0.23.18"],"fixed":["0.23.18"]},{"ecosystem":"Maven","name":"org.http4s:blaze-http_3","purl":"pkg:maven/org.http4s/blaze-http_3","ranges":["<0.23.18"],"fixed":["0.23.18"]},{"ecosystem":"Maven","name":"org.http4s:blaze-http_3","purl":"pkg:maven/org.http4s/blaze-http_3","ranges":[">=1.0.0-M1 <1.0.0-M42"],"fixed":["1.0.0-M42"]},{"ecosystem":"Maven","name":"org.http4s:blaze-http_2.13","purl":"pkg:maven/org.http4s/blaze-http_2.13","ranges":[">=1.0.0-M1 <1.0.0-M42"],"fixed":["1.0.0-M42"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}