{"id":"CVE-2026-53659","title":"http4k is a functional toolkit for Kotlin HTTP applications","summary":"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 decompress…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-409"],"vendor":"http4k","product":"http4k","affected":["http4k < 4.51.0.0","http4k >= 5.0.0.0, < 5.42.0.0","http4k >= 6.0.0.0, < 6.49.0.0"],"patched":["org.http4k:http4k-core 5.42.0.0","org.http4k:http4k-core 6.49.0.0"],"published":"2026-09-14","updated":"2026-09-14","sourceUpdated":"2026-09-14T19:17:25.610","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-53659","references":[{"url":"https://github.com/http4k/http4k/commit/2618fe08f9801353012561ae1f1382fa2d37bac9","label":"security-advisories@github.com"},{"url":"https://github.com/http4k/http4k/commit/9f9e02f8efbbe04e0c70f1c46eef5d9d9067ea5b","label":"security-advisories@github.com"},{"url":"https://github.com/http4k/http4k/releases/tag/6.49.0.0","label":"security-advisories@github.com"},{"url":"https://github.com/http4k/http4k/security/advisories/GHSA-g4w2-6h2r-3m3w","label":"security-advisories@github.com"},{"url":"https://github.com/advisories/GHSA-g4w2-6h2r-3m3w"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53659.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-53659"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2533236"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-53659"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53659"}],"tags":["nvd","cve.org","ghsa","maven","csaf","vex","red-hat"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-09-14T19:03:47.669547Z"},"aliases":["GHSA-g4w2-6h2r-3m3w"],"ecosystem":"maven","ingestedAt":"2026-08-17T22:01:17.029Z","epss":0.00441,"epssPercentile":0.37717,"slug":"CVE-2026-53659","body":"## Overview\n\nhttp4k 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-53659)\n\nAffected packages:\n\n- `org.http4k:http4k-core >= 5.0.0.0, < 5.42.0.0`\n- `org.http4k:http4k-core <= 4.48.2.0`\n- `org.http4k:http4k-core >= 6.0.0.0, < 6.49.0.0`\n\nPatched in:\n\n- `org.http4k:http4k-core 5.42.0.0`\n- `org.http4k:http4k-core 6.49.0.0`\n\nSource: https://github.com/advisories/GHSA-g4w2-6h2r-3m3w\n\n## Vendor advisories\n\n- **Red Hat VEX** · Important · updated 2026-09-18 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53659.json)","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}