What is CVE-2026-40199?

CVE-2026-40199 is a medium-severity vulnerability in Stigtsp Net\, classified under Improper Handling of Length Parameter Inconsistency. CVSS score: 6.5/10. Published 2026-04-10.

How severe is CVE-2026-40199?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in Stigtsp Net\

CVE-2026-40199

Net::CIDR::Lite versions before 0.23 for Perl mishandles IPv4 mapped IPv6 addresses, which may allow IP ACL bypass. _pack_ipv6() includes the sentinel byte from _pack_ipv4() when building the packed representation of IPv4 mapped addresses…

EPSS: 0.003 (22.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N.

Affected products

Stigtsp Net\ — versions \
Stigtsp Net::cidr::lite — versions 0

Weakness classification (CWE)

CWE-130 — Improper Handling of Length Parameter Inconsistency

References

9b29abf9-4ab0-4765-b253-1875cd9b441e (Patch, patch)
9b29abf9-4ab0-4765-b253-1875cd9b441e (release-notes, Release Notes)
9b29abf9-4ab0-4765-b253-1875cd9b441e (related, Third Party Advisory)

Frequently asked questions

What is CVE-2026-40199?: CVE-2026-40199 is a medium-severity vulnerability in Stigtsp Net\, classified under Improper Handling of Length Parameter Inconsistency. CVSS score: 6.5/10. Published 2026-04-10.
How severe is CVE-2026-40199?: Medium severity. CVSS v3 base score is 6.5 out of 10.