# Http4s vulnerabilities Source: https://junglewise.ai/threats/vendors/http4s Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats Updated: 11 November 2026, 03:07 UTC. Rebuilt every hour. Data: https://junglewise.ai/threats/vendors/http4s.json License: CC BY 4.0 with a link back Junglewise Threat Intelligence has tracked 23 vulnerabilities in Http4s: 0 in the last 7 days and 21 in the last 90 days, 2 of them critical and 0 exploited in the wild. The most recent, CVE-2026-61741, was published on 24 September 2026. Nothing in the last four weeks, down from 20 vulnerabilities in the four before. 0 critical against 2. 2 technologies have a page of their own. ## Counts - Last 7 days: 0 - Last 30 days: 0 - Last 90 days: 21 - All time: 23 (2 critical, 0 exploited in the wild) ## About Http4s Typeful, functional, asynchronous HTTP library for Scala. ## Latest Http4s vulnerabilities - [CVE-2026-61741: http4s-scala-xml XXE vulnerability in EntityDecoder](https://junglewise.ai/threats/cve-2026-61741-http4s-scala-xml-xxe-vulnerability-in-entitydecoder) (critical, CVSS 9.3, published 24 Sep 2026) - [CVE-2026-88975: Http4s Ember HTTP/2 frame buffering denial of service](https://junglewise.ai/threats/cve-2026-88975-http4s-ember-http-2-frame-buffering-denial-of-service) (high, CVSS 7.5, published 15 Sep 2026) - [CVE-2026-69218: Http4s Ember HTTP/2 unbounded continuation frame accumulation](https://junglewise.ai/threats/cve-2026-69218-http4s-ember-http-2-unbounded-continuation-frame-accumulation) (high, CVSS 7.5, published 15 Sep 2026) - [CVE-2026-69217: Http4s Ember HTTP/1.1 parser request smuggling via duplicate Content-Length](https://junglewise.ai/threats/cve-2026-69217-http4s-ember-http-1-1-parser-request-smuggling-via-duplicate) (high, CVSS 8.7, published 15 Sep 2026) - [CVE-2026-69215: Http4s CookieJar middleware cookie leakage via substring matching](https://junglewise.ai/threats/cve-2026-69215-http4s-cookiejar-middleware-cookie-leakage-via-substring-matching) (medium, CVSS 6.8, published 15 Sep 2026) - [CVE-2026-69210: Http4s WebSocket decoder negative length handling denial of service](https://junglewise.ai/threats/cve-2026-69210-http4s-websocket-decoder-negative-length-handling-denial-of) (high, CVSS 7.5, published 15 Sep 2026) - [CVE-2026-69206: Http4s DigestAuth replay attack in authorization header](https://junglewise.ai/threats/cve-2026-69206-http4s-digestauth-replay-attack-in-authorization-header) (medium, CVSS 5.9, published 15 Sep 2026) - [CVE-2026-69205: Http4s Ember HTTP request smuggling via Transfer-Encoding parsing](https://junglewise.ai/threats/cve-2026-69205-http4s-ember-http-request-smuggling-via-transfer-encoding-parsing) (high, CVSS 8.7, published 15 Sep 2026) - [CVE-2026-69203: Http4s Ember HTTP/2 stream limit enforcement bypass](https://junglewise.ai/threats/cve-2026-69203-http4s-ember-http-2-stream-limit-enforcement-bypass) (high, CVSS 7.5, published 15 Sep 2026) - [CVE-2026-69202: Http4s Ember HTTP/2 unbounded inbound body buffering](https://junglewise.ai/threats/cve-2026-69202-http4s-ember-http-2-unbounded-inbound-body-buffering) (high, CVSS 7.5, published 15 Sep 2026) - [CVE-2026-69216: Http4s Ember chunk parser lenience in HTTP request smuggling](https://junglewise.ai/threats/cve-2026-69216-http4s-ember-chunk-parser-lenience-in-http-request-smuggling) (medium, CVSS 5.4, published 15 Sep 2026) - [CVE-2026-69214: Http4s CookieJar middleware accepts arbitrary Set-Cookie domain](https://junglewise.ai/threats/cve-2026-69214-http4s-cookiejar-middleware-accepts-arbitrary-set-cookie-domain) (medium, CVSS 6.8, published 15 Sep 2026) - [CVE-2026-69213: Http4s Ember HTTP/2 unbounded outbound frame queue denial of service](https://junglewise.ai/threats/cve-2026-69213-http4s-ember-http-2-unbounded-outbound-frame-queue-denial-of) (high, CVSS 7.5, published 15 Sep 2026) - [CVE-2026-69212: Http4s FollowRedirect credential leak on scheme downgrade](https://junglewise.ai/threats/cve-2026-69212-http4s-followredirect-credential-leak-on-scheme-downgrade) (medium, CVSS 5.9, published 15 Sep 2026) - [CVE-2026-69211: Http4s ResponseCookie header injection via unescaped attributes](https://junglewise.ai/threats/cve-2026-69211-http4s-responsecookie-header-injection-via-unescaped-attributes) (medium, CVSS 4.8, published 15 Sep 2026) - [CVE-2026-69209: http4s WebSocket decoder unbounded message buffering](https://junglewise.ai/threats/cve-2026-69209-http4s-websocket-decoder-unbounded-message-buffering) (high, CVSS 7.5, published 15 Sep 2026) - [CVE-2026-69208: Http4s DigestAuth memory exhaustion via unbounded nonce cache](https://junglewise.ai/threats/cve-2026-69208-http4s-digestauth-memory-exhaustion-via-unbounded-nonce-cache) (high, CVSS 7.5, published 15 Sep 2026) - [CVE-2026-69204: Http4s Ember HTTP request smuggling via Transfer-Encoding and Content-Length](https://junglewise.ai/threats/cve-2026-69204-http4s-ember-http-request-smuggling-via-transfer-encoding-and) (critical, CVSS 4, published 15 Sep 2026) - [CVE-2026-69201: Http4s ResourceService and WebjarService path traversal via percent-encoded separators](https://junglewise.ai/threats/cve-2026-69201-http4s-resourceservice-and-webjarservice-path-traversal-via) (medium, CVSS 5.9, published 15 Sep 2026) - [CVE-2026-73494: http4s blaze HTTP/1.1 parser conformance bypass](https://junglewise.ai/threats/cve-2026-73494-http4s-blaze-http-1-1-parser-conformance-bypass) (high, CVSS 7.4, published 14 Sep 2026) - [CVE-2026-54556: http4s HTTP/2 denial of service in HPACK header compression](https://junglewise.ai/threats/cve-2026-54556-http4s-http-2-denial-of-service-in-hpack-header-compression) (high, CVSS 4, published 26 Aug 2026) - [CVE-2026-73495: http4s blaze HTTP/1.1 trailer header injection](https://junglewise.ai/threats/cve-2026-73495-http4s-blaze-http-1-1-trailer-header-injection) (high, CVSS 7.4, published 12 Aug 2026) - [CVE-2026-73493: Http4s blaze-server unbounded WebSocket message aggregation](https://junglewise.ai/threats/cve-2026-73493-http4s-blaze-server-unbounded-websocket-message-aggregation) (high, CVSS 7.5, published 12 Aug 2026) ## Most severe Http4s vulnerabilities - [CVE-2026-61741: http4s-scala-xml XXE vulnerability in EntityDecoder](https://junglewise.ai/threats/cve-2026-61741-http4s-scala-xml-xxe-vulnerability-in-entitydecoder) (critical, CVSS 9.3, published 24 Sep 2026) - [CVE-2026-69204: Http4s Ember HTTP request smuggling via Transfer-Encoding and Content-Length](https://junglewise.ai/threats/cve-2026-69204-http4s-ember-http-request-smuggling-via-transfer-encoding-and) (critical, CVSS 4, published 15 Sep 2026) - [CVE-2026-69217: Http4s Ember HTTP/1.1 parser request smuggling via duplicate Content-Length](https://junglewise.ai/threats/cve-2026-69217-http4s-ember-http-1-1-parser-request-smuggling-via-duplicate) (high, CVSS 8.7, published 15 Sep 2026) - [CVE-2026-69205: Http4s Ember HTTP request smuggling via Transfer-Encoding parsing](https://junglewise.ai/threats/cve-2026-69205-http4s-ember-http-request-smuggling-via-transfer-encoding-parsing) (high, CVSS 8.7, published 15 Sep 2026) - [CVE-2026-69208: Http4s DigestAuth memory exhaustion via unbounded nonce cache](https://junglewise.ai/threats/cve-2026-69208-http4s-digestauth-memory-exhaustion-via-unbounded-nonce-cache) (high, CVSS 7.5, published 15 Sep 2026) - [CVE-2026-88975: Http4s Ember HTTP/2 frame buffering denial of service](https://junglewise.ai/threats/cve-2026-88975-http4s-ember-http-2-frame-buffering-denial-of-service) (high, CVSS 7.5, published 15 Sep 2026) - [CVE-2026-69218: Http4s Ember HTTP/2 unbounded continuation frame accumulation](https://junglewise.ai/threats/cve-2026-69218-http4s-ember-http-2-unbounded-continuation-frame-accumulation) (high, CVSS 7.5, published 15 Sep 2026) - [CVE-2026-69210: Http4s WebSocket decoder negative length handling denial of service](https://junglewise.ai/threats/cve-2026-69210-http4s-websocket-decoder-negative-length-handling-denial-of) (high, CVSS 7.5, published 15 Sep 2026) - [CVE-2026-69203: Http4s Ember HTTP/2 stream limit enforcement bypass](https://junglewise.ai/threats/cve-2026-69203-http4s-ember-http-2-stream-limit-enforcement-bypass) (high, CVSS 7.5, published 15 Sep 2026) - [CVE-2026-69202: Http4s Ember HTTP/2 unbounded inbound body buffering](https://junglewise.ai/threats/cve-2026-69202-http4s-ember-http-2-unbounded-inbound-body-buffering) (high, CVSS 7.5, published 15 Sep 2026) ## Vulnerabilities per week Nothing in the last four weeks, down from 20 vulnerabilities in the four before. 0 critical against 2. | Week of | Vulns | Critical | Exploited | | --- | --- | --- | --- | | 17 Aug 2026 | 0 | 0 | 0 | | 24 Aug 2026 | 1 | 0 | 0 | | 31 Aug 2026 | 0 | 0 | 0 | | 7 Sep 2026 | 0 | 0 | 0 | | 14 Sep 2026 | 19 | 1 | 0 | | 21 Sep 2026 | 1 | 1 | 0 | | 28 Sep 2026 | 0 | 0 | 0 | | 5 Oct 2026 | 0 | 0 | 0 | | 12 Oct 2026 | 0 | 0 | 0 | | 19 Oct 2026 | 0 | 0 | 0 | | 26 Oct 2026 | 0 | 0 | 0 | | 2 Nov 2026 | 0 | 0 | 0 | | 9 Nov 2026 | 0 | 0 | 0 | ## Http4s technologies - [Http4s-Ember-Core](https://junglewise.ai/threats/technologies/http4s-ember-core): 10 vulnerabilities - [Http4s](https://junglewise.ai/threats/technologies/http4s): 6 vulnerabilities ## Sources NVD, GitHub Security Advisories, OSV, the CISA Known Exploited Vulnerabilities catalog, FIRST EPSS and vendor advisories. Rebuilt every hour. Cite as: Junglewise Threat Intelligence, "Http4s vulnerabilities", https://junglewise.ai/threats/vendors/http4s, 11 November 2026.