CVE-2026-121727 is a high-severity (CVSS 7.5) CWE-191 vulnerability. The records list no fixed version yet; check the vendor advisory below and apply the mitigations in the meantime.
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…
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.
Detection & mitigation playbook
VulnerabilityDetect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).
Remediation status
The records we use list no fixed release for CVE-2026-121727. Check the upstream advisory for a patched version, and apply the exposure-reduction steps below in the meantime.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Frequently Asked Questions
Is CVE-2026-121727 in your dependencies?
Find it across your dependency tree, including transitive dependencies.