What is CVE-2026-45409?

CVE-2026-45409 is a medium-severity vulnerability in Kjd Idna, classified under Inefficient Regular Expression Complexity. CVSS score: 5.3/10. Published 2026-06-05.

How severe is CVE-2026-45409?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Vulnerability in Kjd Idna

CVE-2026-45409

Internationalized Domain Names in Applications (IDNA) for Python provides support for Internationalized Domain Names in Applications (IDNA) and Unicode IDNA Compatibility Processing. In versions prior to 3.15, payloads such as `"\u0660" *…

Vulnerability class: ReDoS (Regular Expression Denial of Service)

EPSS: 0.004 (33.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

Affected products

Kjd Idna — versions < 3.15
Kjd Internationalized_domain_names_in_applications

Weakness classification (CWE)

CWE-1333 — Inefficient Regular Expression Complexity

References

security-advisories@github.com (x_refsource_CONFIRM, Mitigation, Vendor Advisory)

Frequently asked questions

What is CVE-2026-45409?: CVE-2026-45409 is a medium-severity vulnerability in Kjd Idna, classified under Inefficient Regular Expression Complexity. CVSS score: 5.3/10. Published 2026-06-05.
How severe is CVE-2026-45409?: Medium severity. CVSS v3 base score is 5.3 out of 10.