blaze: Multiple HTTP/1.1 request-smuggling primitives in blaze's Java wire parser

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-73494
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-14 18:19:58 UTC
Updated2026-09-14 20:16:50 UTC
Descriptionblaze 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.

Risk And Classification

Primary CVSS: v3.1 7.4 HIGH from [email protected]

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS: 0.003740000 probability, percentile 0.309370000 (date 2026-09-15)

Problem Types: CWE-444 | CWE-444 CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.4HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
3.1CNADECLARED7.4HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Http4s Blaze affected < 0.23.18 Not specified
CNA Http4s Blaze affected >= 1.0.0-M1, < 1.0.0-M42 Not specified
CNA Org.http4s Blaze-http 2.13 affected < 0.23.18 Not specified
CNA Org.http4s Blaze-http 2.13 affected >= 1.0.0-M1, < 1.0.0-M42 Not specified
CNA Org.http4s Blaze-http 3 affected < 0.23.18 Not specified
CNA Org.http4s Blaze-http 3 affected >= 1.0.0-M1, < 1.0.0-M42 Not specified
CNA Org.http4s Http4s-blaze-server 2.13 affected < 0.23.18 Not specified

References

ReferenceSourceLinkTags
github.com/http4s/blaze/commit/e871ebb1d27f50c98fd56988526ce42d0fee74d6 [email protected] github.com
github.com/http4s/blaze/commit/4eec2007806aa9acfefb00ebb636ddc39a147a96 [email protected] github.com
github.com/http4s/blaze/releases/tag/v1.0.0-M42 [email protected] github.com
github.com/http4s/blaze/commit/a54bc9cd31758335c7f24e29763622fd03fcf734 [email protected] github.com
github.com/http4s/blaze/commit/3f7c022e306631b006dcb43a1d7f65c0d1966f17 [email protected] github.com
github.com/http4s/blaze/commit/c47d9675f87603f11b32a11d503626bdf9be5c7a [email protected] github.com
github.com/http4s/blaze/security/advisories/GHSA-mhvj-jhpq-885v [email protected] github.com
github.com/http4s/blaze/releases/tag/v0.23.18 [email protected] github.com
github.com/http4s/blaze/commit/927b67753a78c13c4445dac9307f511f5c4878c3 [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

© CVE.report 2026

Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. It is the responsibility of user to evaluate the accuracy, completeness or usefulness of any information, opinion, advice or other content. EACH USER WILL BE SOLELY RESPONSIBLE FOR ANY consequences of his or her direct or indirect use of this web site. ALL WARRANTIES OF ANY KIND ARE EXPRESSLY DISCLAIMED. This site will NOT BE LIABLE FOR ANY DIRECT, INDIRECT or any other kind of loss.

CVE, CWE, and OVAL are registred trademarks of The MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. This site includes MITRE data granted under the following license.

Free CVE JSON API cve.report/api

CVE.report and Source URL Uptime Status status.cve.report