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Fencer Intel
high 7.5

CVE-2025-40928 json

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

published last yr. modified 4mo ago also EUVD-2025-27141

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 53%
public exploits
0
none known

Summary

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

Patch / fix

  • MLEHMANN JSON::XS 4.04
  • libjson-xs-perl Debian 12 4.040-1~deb12u1
  • libjson-xs-perl Debian 13 4.040-1~deb13u1
  • libjson-xs-perl Debian 14 4.030-3

debian advisories DEBIAN-CVE-2025-40928

  • libjson-xs-perl Ubuntu 22.04 LTS 4.040-0ubuntu0.22.04.1
  • libjson-xs-perl Ubuntu 24.04 LTS 4.040-0ubuntu0.24.04.1
  • libjson-xs-perl Ubuntu 26.10, Ubuntu 26.04 LTS, Ubuntu 25.10 4.040-1

ubuntu advisories UBUNTU-CVE-2025-40928

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • perl-JSON-XS RHEL 8 1:3.04-4.el8_10
  • perl-JSON-XS RHEL 9 1:4.04-1.el9_6
  • perl-JSON-XS RHEL 10.0 1:4.04-1.el10_0
  • perl-JSON-XS RHEL 9.4 EUS 1:4.03-5.el9_4.1

red hat advisories RHSA-2025:17430RHSA-2025:17163RHSA-2025:17162RHSA-2025:17119

  • perl-JSON-XS openSUSE Tumbleweed 4.40.0-1.1

opensuse advisories openSUSE-SU-2025:15535-1

  • perl-JSON-XS AlmaLinux 9 1:4.04-1.el9_6
  • perl-JSON-XS AlmaLinux 8 1:3.04-4.el8_10
  • perl-JSON-XS AlmaLinux 10 1:4.04-1.el10_0

almalinux advisories ALSA-2025:17162ALSA-2025:17163ALSA-2025:17119

  • perl-JSON-XS Rocky Linux 9 1:4.04-1.el9_6
  • perl-JSON-XS Rocky Linux 10 1:4.04-1.el10_0
  • perl-JSON-XS Rocky Linux 8 1:3.04-4.el8_10

rocky linux advisories RLSA-2025:17162RLSA-2025:17119RLSA-2025:17163

  • perl-JSON-XS CBL-Mariner 2.0, Azure Linux 3.0 4.04-1

azure linux advisories AZL-67076AZL-67079

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-40928 updated cvss 7.5

JSON-XS: integer buffer overflow causing a segfault when parsing crafted JSON

  • Red Hat CodeReady Linux Builder EUS (v.9.4) perl-JSON-XS 4.03-5.el9_4.1
    fixed: vendor fix RHSA-2025:17430
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) perl-JSON-XS 4.04-1.el9_6
    fixed: vendor fix RHSA-2025:17162
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) perl-JSON-XS 4.04-1.el10_0
    fixed: vendor fix RHSA-2025:17119
  • Red Hat Enterprise Linux CRB (v. 8) perl-JSON-XS 3.04-4.el8_10
    fixed: vendor fix RHSA-2025:17163

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
last yr.

Exploit prediction

0.70% chance of exploitation in the next 30 days, higher than 53% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • MLEHMANN JSON::XS

Classification

Weakness
  • CWE-122 Heap-based Buffer Overflow

References

Sources

Fencer Intel 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.