CVE-2026-121727: jorisvink kore · Integer Underflow
Affects jorisvink koreSource CVE Database V5
Not known to be exploited · CVSS 8.7 High : upgrade to 4.3.0 soon.
Data as of 3 Nov 2026, 23:28 UTC
Thin evidence
One scorer or none| CNA (VulnCheck) | CVSS 4.0 | 8.7 |
|---|---|---|
| CNA (VulnCheck) | CVSS 3.1 | 7.5 |
- Patch
- Available – fixed in 4.3.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 3 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 3 Nov 2026.
What to do
Upgrade jorisvink kore to 4.3.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| jorisvinkkore | Affected
| Fixed in
|
GitHubkorepkg:github/koreOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
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.
References
- github.com/jorisvink/kore/commit/1ff3c0f6f7973dc7fc8bf38369790ef2d8079b3b (opens in a new tab)
- github.com/jorisvink/kore (opens in a new tab)
- kore.io/releases/4.3.0 (opens in a new tab)
- github.com/jorisvink/kore/blob/4.3.0-rc5/src/http.c (opens in a new tab)
- vulncheck.com/advisories/kore-before-4.3.0-integer-underflow-memory-exhaustion-via-http-header-recv (opens in a new tab)