What is CVE-2025-40928?

CVE-2025-40928 is a high-severity vulnerability in Mlehmann Json::xs, classified under Heap-based Buffer Overflow. CVSS score: 7.5/10. Published 2025-09-08.

How severe is CVE-2025-40928?

High severity. CVSS v3 base score is 7.5 out of 10.

Is CVE-2025-40928 known to be exploited?

3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Buffer overflow in Mlehmann Json::xs

CVE-2025-40928

JSON::XS before version 4.04 for Perl has an integer buffer overflow causing a segfault when parsing crafted JSON, enabling denial-of-service attacks or other unspecified impact

Vulnerability class: Buffer Overflow

EPSS: 0.006 (44.4th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Mlehmann Json::xs — versions 0

Weakness classification (CWE)

CWE-122 — Heap-based Buffer Overflow

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-40928?: CVE-2025-40928 is a high-severity vulnerability in Mlehmann Json::xs, classified under Heap-based Buffer Overflow. CVSS score: 7.5/10. Published 2025-09-08.
How severe is CVE-2025-40928?: High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2025-40928 known to be exploited?: 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.