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4 vulnerabilities by org.http4s
CVE-2026-73494 (GCVE-0-2026-73494)
Vulnerability from nvd – Published: 2026-09-14 17:33 – Updated: 2026-09-14 20:05
VLAI
EPSS
VEX
Title
blaze: Multiple HTTP/1.1 request-smuggling primitives in blaze's Java wire parser
Summary
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.
Severity
7.4 (High)
SSVC
Exploitation: none
Automatable: no
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-14 19:21 UTC
CWE
- CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
Assigner
References
9 references
| URL | Tags |
|---|---|
| https://github.com/http4s/blaze/security/advisori… | x_refsource_CONFIRM |
| https://github.com/http4s/blaze/commit/3f7c022e30… | x_refsource_MISC |
| https://github.com/http4s/blaze/commit/4eec200780… | x_refsource_MISC |
| https://github.com/http4s/blaze/commit/927b67753a… | x_refsource_MISC |
| https://github.com/http4s/blaze/commit/a54bc9cd31… | x_refsource_MISC |
| https://github.com/http4s/blaze/commit/c47d9675f8… | x_refsource_MISC |
| https://github.com/http4s/blaze/commit/e871ebb1d2… | x_refsource_MISC |
| https://github.com/http4s/blaze/releases/tag/v0.23.18 | x_refsource_MISC |
| https://github.com/http4s/blaze/releases/tag/v1.0.0-M42 | x_refsource_MISC |
Impacted products
4 products
| Vendor | Product | Version | |
|---|---|---|---|
| http4s | blaze |
Affected:
< 0.23.18
Affected: >= 1.0.0-M1, < 1.0.0-M42 |
|
| org.http4s | blaze-http_2.13 |
Affected:
< 0.23.18
Affected: >= 1.0.0-M1, < 1.0.0-M42 |
|
| org.http4s | blaze-http_3 |
Affected:
< 0.23.18
Affected: >= 1.0.0-M1, < 1.0.0-M42 |
|
| org.http4s | http4s-blaze-server_2.13 |
Affected:
< 0.23.18
|
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CVE-2026-54556 (GCVE-0-2026-54556)
Vulnerability from nvd – Published: 2026-08-26 14:10 – Updated: 2026-08-29 02:38
VLAI
EPSS
VEX
Title
Http4s: HTTP/2 Denial of Service with Ember Backend
Summary
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, an unauthenticated HTTP/2 peer can cause an out-of-memory denial of service in the Ember backend with HTTP/2 enabled. The Hpack wrapper in ember-core/shared/src/main/scala/org/http4s/ember/core/h2/Hpack.scala concatenates HEADERS and CONTINUATION frame fragments and decodes them into a single List, but maxHeaderSize accounting does not include indexed headers or HPACK per-header overhead. A small compressed header block can therefore expand into a much larger decoded representation that remains in memory for processing. Servers exposed to untrusted HTTP/2 traffic and clients directed to an untrusted HTTP/2 server are affected, and concurrent malicious connections can exhaust the process heap. This issue is fixed in versions 0.23.35 and 1.0.0-M47.
Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-29 02:38 UTC
CWE
- CWE-409 - Improper Handling of Highly Compressed Data (Data Amplification)
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://github.com/http4s/http4s/security/advisor… | x_refsource_CONFIRM |
| https://github.com/http4s/http4s/commit/6e8eccd64… | x_refsource_MISC |
| https://github.com/http4s/http4s/releases/tag/v0.23.35 | x_refsource_MISC |
| https://github.com/http4s/http4s/releases/tag/v1.… | x_refsource_MISC |
Impacted products
4 products
| Vendor | Product | Version | |
|---|---|---|---|
| http4s | http4s |
Affected:
< 0.23.35
Affected: >= 1.0.0-M1, < 1.0.0-M46 |
|
| org.http4s | http4s-ember-core_2.12 |
Affected:
< 0.23.35
|
|
| org.http4s | http4s-ember-core_2.13 |
Affected:
>= 1.0.0-M1, < 1.0.0-M46
Affected: < 0.23.35 |
|
| org.http4s | http4s-ember-core_3 |
Affected:
>= 1.0.0-M1, < 1.0.0-M46
Affected: < 0.23.35 |
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CVE-2026-73494 (GCVE-0-2026-73494)
Vulnerability from cvelistv5 – Published: 2026-09-14 17:33 – Updated: 2026-09-14 20:05
VLAI
EPSS
VEX
Title
blaze: Multiple HTTP/1.1 request-smuggling primitives in blaze's Java wire parser
Summary
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.
Severity
7.4 (High)
SSVC
Exploitation: none
Automatable: no
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-14 19:21 UTC
CWE
- CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
Assigner
References
9 references
| URL | Tags |
|---|---|
| https://github.com/http4s/blaze/security/advisori… | x_refsource_CONFIRM |
| https://github.com/http4s/blaze/commit/3f7c022e30… | x_refsource_MISC |
| https://github.com/http4s/blaze/commit/4eec200780… | x_refsource_MISC |
| https://github.com/http4s/blaze/commit/927b67753a… | x_refsource_MISC |
| https://github.com/http4s/blaze/commit/a54bc9cd31… | x_refsource_MISC |
| https://github.com/http4s/blaze/commit/c47d9675f8… | x_refsource_MISC |
| https://github.com/http4s/blaze/commit/e871ebb1d2… | x_refsource_MISC |
| https://github.com/http4s/blaze/releases/tag/v0.23.18 | x_refsource_MISC |
| https://github.com/http4s/blaze/releases/tag/v1.0.0-M42 | x_refsource_MISC |
Impacted products
4 products
| Vendor | Product | Version | |
|---|---|---|---|
| http4s | blaze |
Affected:
< 0.23.18
Affected: >= 1.0.0-M1, < 1.0.0-M42 |
|
| org.http4s | blaze-http_2.13 |
Affected:
< 0.23.18
Affected: >= 1.0.0-M1, < 1.0.0-M42 |
|
| org.http4s | blaze-http_3 |
Affected:
< 0.23.18
Affected: >= 1.0.0-M1, < 1.0.0-M42 |
|
| org.http4s | http4s-blaze-server_2.13 |
Affected:
< 0.23.18
|
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CVE-2026-54556 (GCVE-0-2026-54556)
Vulnerability from cvelistv5 – Published: 2026-08-26 14:10 – Updated: 2026-08-29 02:38
VLAI
EPSS
VEX
Title
Http4s: HTTP/2 Denial of Service with Ember Backend
Summary
Http4s is a Scala interface for HTTP services. Prior to 0.23.35 and 1.0.0-M47, an unauthenticated HTTP/2 peer can cause an out-of-memory denial of service in the Ember backend with HTTP/2 enabled. The Hpack wrapper in ember-core/shared/src/main/scala/org/http4s/ember/core/h2/Hpack.scala concatenates HEADERS and CONTINUATION frame fragments and decodes them into a single List, but maxHeaderSize accounting does not include indexed headers or HPACK per-header overhead. A small compressed header block can therefore expand into a much larger decoded representation that remains in memory for processing. Servers exposed to untrusted HTTP/2 traffic and clients directed to an untrusted HTTP/2 server are affected, and concurrent malicious connections can exhaust the process heap. This issue is fixed in versions 0.23.35 and 1.0.0-M47.
Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-29 02:38 UTC
CWE
- CWE-409 - Improper Handling of Highly Compressed Data (Data Amplification)
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://github.com/http4s/http4s/security/advisor… | x_refsource_CONFIRM |
| https://github.com/http4s/http4s/commit/6e8eccd64… | x_refsource_MISC |
| https://github.com/http4s/http4s/releases/tag/v0.23.35 | x_refsource_MISC |
| https://github.com/http4s/http4s/releases/tag/v1.… | x_refsource_MISC |
Impacted products
4 products
| Vendor | Product | Version | |
|---|---|---|---|
| http4s | http4s |
Affected:
< 0.23.35
Affected: >= 1.0.0-M1, < 1.0.0-M46 |
|
| org.http4s | http4s-ember-core_2.12 |
Affected:
< 0.23.35
|
|
| org.http4s | http4s-ember-core_2.13 |
Affected:
>= 1.0.0-M1, < 1.0.0-M46
Affected: < 0.23.35 |
|
| org.http4s | http4s-ember-core_3 |
Affected:
>= 1.0.0-M1, < 1.0.0-M46
Affected: < 0.23.35 |
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