njs through 0.3.1, used in NGINX, has a heap-based buffer overflow in nxt_utf8_encode in nxt_utf8.c.

published 2019-05-20 7 y ago modified 2026-06-17 4 mo ago also EUVD-2019-3851

cvss: 9.8; version 3.0, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 2.0%; EPSS 2.0% chance of exploitation in 30 days, percentile 80%
public exploits: 0; none known

Exploit prediction

1.99% chance of exploitation in the next 30 days, higher than 80% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/nginx/njs/issues/162 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
NVD	3.0	9.8	CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD	2.0	7.5	AV:N/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness

CWE-787 Out-of-bounds Write

References

github.com /nginx/njs/issues/162
exploit, third-party-advisory

Sources

CVE List CVE-2019-12206
NVD CVE-2019-12206

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary