CVE-2026-121727

High

Description

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.

SeverityHigh

CVSS7.5

Exploit probability—

ProductJorisvink Kore

PublishedNov 3, 2026

First seenNov 4, 2026

Weakness typeCWE-191CWE-191

How to fix

Update

jorisvink kore4.3.0 or later

Patches

github.com/jorisvink/kore/commit/1ff3c0f6f7973dc7fc8bf38369790ef2d8079b3b

Vendor advisories

kore.io/releases/4.3.0

Affected products

Product	Affected versions	Fixed in
jorisvink kore	v < 4.3.0	4.3.0

Check your version

Choose the product and enter the version you run to see whether it falls in the affected range.

In the Intelligence 360 plan

Attack Surface Management

See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.