CVE-2026-53659

http4k is a functional toolkit for Kotlin HTTP applications. Prior to 4.51.0.0, 5.42.0.0, and 6.49.0.0, ServerFilters.GZip, RequestFilters.GunZip, and the underlying Gzip request-body decompression functions impose no limit on decompressed size. An unauthenticated client can send a small gzip-encoded request body that expands to gigabytes, exhausting the JVM heap and denying service to other clients. The fix uses SizeLimitedInputStream to enforce a default 10 MiB limit, causes ServerFilters.GZip and RequestFilters.GunZip to return 413 Request Entity Too Large, and causes other decompression paths to throw SizeLimitExceededException. This issue is fixed in versions 4.51.0.0, 5.42.0.0, and 6.49.0.0.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/http4k/http4k/commit/2618fe08f9801353012561ae1f1382fa2d37bac9
https://github.com/http4k/http4k/commit/9f9e02f8efbbe04e0c70f1c46eef5d9d9067ea5b
https://github.com/http4k/http4k/releases/tag/6.49.0.0
https://github.com/http4k/http4k/security/advisories/GHSA-g4w2-6h2r-3m3w

Configurations

No configuration.

History

No history.

Information

Published : 2026-09-14 18:17

Updated : 2026-09-14 19:17

NVD link : CVE-2026-53659

Mitre link : CVE-2026-53659

CVE.ORG link : CVE-2026-53659

JSON object : View

Products Affected

No product.

CWE

CWE-409

Improper Handling of Highly Compressed Data (Data Amplification)

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