{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-73495", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-08-12T19:00:33.735Z", "datePublished": "2026-08-12T21:11:55.180Z", "dateUpdated": "2026-08-12T21:11:55.180Z"}, "containers": {"cna": {"title": "blaze: Chunked-body trailer fields promoted into Request.headers in blaze-server (front-end header-sanitization bypass)", "problemTypes": [{"descriptions": [{"cweId": "CWE-444", "lang": "en", "description": "CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 7.4, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N", "version": "3.1"}}], "references": [{"name": "https://github.com/http4s/blaze/security/advisories/GHSA-46q4-43ph-c6fr", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/http4s/blaze/security/advisories/GHSA-46q4-43ph-c6fr"}, {"name": "https://github.com/http4s/blaze/commit/ef3e666c146cfc16cb6603f1fc3c464daab4a24f", "tags": ["x_refsource_MISC"], "url": "https://github.com/http4s/blaze/commit/ef3e666c146cfc16cb6603f1fc3c464daab4a24f"}, {"name": "https://github.com/http4s/blaze/releases/tag/v0.23.18", "tags": ["x_refsource_MISC"], "url": "https://github.com/http4s/blaze/releases/tag/v0.23.18"}, {"name": "https://github.com/http4s/blaze/releases/tag/v1.0.0-M42", "tags": ["x_refsource_MISC"], "url": "https://github.com/http4s/blaze/releases/tag/v1.0.0-M42"}], "affected": [{"vendor": "http4s", "product": "blaze", "versions": [{"version": "< 0.23.18", "status": "affected"}, {"version": ">= 1.0.0-M1, < 1.0.0-M42", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-08-12T21:11:55.180Z"}, "descriptions": [{"lang": "en", "value": "blaze is a Scala library for building asynchronous pipelines, with a focus on network IO. Prior to 0.23.18 and 1.0.0-M42, blaze-server can merge HTTP/1.1 chunked-body trailer fields into Request.headers. Because trailer fields are attacker-controlled, an unauthenticated remote client can inject arbitrary header names and values, including X-Forwarded-For and internal authorization headers, that a fronting proxy sanitized from the request-header section, bypassing header-based trust decisions in the application. Any http4s application using BlazeServerBuilder over HTTP/1.1 whose routes or middleware trust proxy-set headers, including X-Forwarded-For, X-Real-IP, and X-Forwarded-Host, is affected. If a fronting proxy strips or normalizes those headers but forwards chunked bodies with trailers intact, an attacker can spoof client IP for allow-lists, rate limits, or auditing, forge the https scheme, or inject internal authorization headers. A promoted Connection: close trailer is also honored, allowing attacker-controlled termination of pooled backend connections. This issue is fixed in versions 0.23.18 and 1.0.0-M42."}], "source": {"advisory": "GHSA-46q4-43ph-c6fr", "discovery": "UNKNOWN"}}}}

{}

{"affected": [{"affectedData": [{"product": "blaze", "vendor": "http4s", "versions": [{"status": "affected", "version": "< 0.23.18"}, {"status": "affected", "version": ">= 1.0.0-M1, < 1.0.0-M42"}]}], "source": "[email protected]"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "blaze is a Scala library for building asynchronous pipelines, with a focus on network IO. Prior to 0.23.18 and 1.0.0-M42, blaze-server can merge HTTP/1.1 chunked-body trailer fields into Request.headers. Because trailer fields are attacker-controlled, an unauthenticated remote client can inject arbitrary header names and values, including X-Forwarded-For and internal authorization headers, that a fronting proxy sanitized from the request-header section, bypassing header-based trust decisions in the application. Any http4s application using BlazeServerBuilder over HTTP/1.1 whose routes or middleware trust proxy-set headers, including X-Forwarded-For, X-Real-IP, and X-Forwarded-Host, is affected. If a fronting proxy strips or normalizes those headers but forwards chunked bodies with trailers intact, an attacker can spoof client IP for allow-lists, rate limits, or auditing, forge the https scheme, or inject internal authorization headers. A promoted Connection: close trailer is also honored, allowing attacker-controlled termination of pooled backend connections. This issue is fixed in versions 0.23.18 and 1.0.0-M42."}], "id": "CVE-2026-73495", "lastModified": "2026-08-12T22:17:16.820", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 7.4, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N", "version": "3.1"}, "exploitabilityScore": 2.2, "impactScore": 5.2, "source": "[email protected]", "type": "Secondary"}]}, "published": "2026-08-12T22:17:16.820", "references": [{"source": "[email protected]", "url": "https://github.com/http4s/blaze/commit/ef3e666c146cfc16cb6603f1fc3c464daab4a24f"}, {"source": "[email protected]", "url": "https://github.com/http4s/blaze/releases/tag/v0.23.18"}, {"source": "[email protected]", "url": "https://github.com/http4s/blaze/releases/tag/v1.0.0-M42"}, {"source": "[email protected]", "url": "https://github.com/http4s/blaze/security/advisories/GHSA-46q4-43ph-c6fr"}], "sourceIdentifier": "[email protected]", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-444"}], "source": "[email protected]", "type": "Primary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,0.23.18)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[1.0.0-M1,1.0.0-M42)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "blaze", "source": "cna", "vendor": "http4s"}, "product": "blaze", "vendor": "http4s"}], "created": "2026-08-12T23:00:05.002136+00:00", "updated": "2026-08-12T23:00:05.002170+00:00", "vendors": ["http4s", "http4s$PRODUCT$blaze"]}