Integer overflow in Jorisvink Kore
CVE-2026-121727
Kore before 4.3.0 contains an integer underflow vulnerability in HTTP request body handling that allows unauthenticated attackers to bypass http_body_max by sending more body bytes than declared. Attackers can send oversized first segments over many concurrent POST, PUT or DELETE connections, wrapping content_length to grow buffers unbounded and exhaust worker memory.
Published .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/jorisvink/kore/commit/1ff3c0f6f7973dc7fc8bf38369790ef2d8079b3b (patch)
- github.com/jorisvink/kore (product)
- kore.io/releases/4.3.0 (release-notes)
- github.com/jorisvink/kore/blob/4.3.0-rc5/src/http.c (technical-description)
- www.vulncheck.com/advisories/kore-before-4.3.0-integer-underflow-memory-exhaust… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-121727?
- CVE-2026-121727 is a high-severity vulnerability in Jorisvink Kore, classified under Integer Underflow. CVSS score: 7.5/10. Published 2026-11-03.
- How severe is CVE-2026-121727?
- High severity. CVSS v3 base score is 7.5 out of 10.