How severe is CVE-2025-40929?

CVE-2025-40929 has a CVSS 3.x base score of 5.6, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.

Is CVE-2025-40929 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (33rd percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2025-40929?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2025-40929 have an EU (EUVD) identifier?

Yes. CVE-2025-40929 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-27140.

When was CVE-2025-40929 published?

CVE-2025-40929 was published on 2025-09-08 and last updated on 2026-06-17.

CVE-2025-40929

CVE-2025-40929 is a medium-severity vulnerability with a CVSS 3.x base score of 5.6. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-122.

Key facts

Severity: Medium (CVSS 3.x base score 5.6)
EPSS exploit prediction: 0% (33rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-27140
Weakness: CWE-122
Published: 2025-09-08
Last modified: 2026-06-17

Description

Cpanel::JSON::XS before version 4.40 for Perl has an integer buffer overflow causing a segfault when parsing crafted JSON, enabling denial-of-service attacks or other unspecified impact

Frequently asked questions

What is CVE-2025-40929?: Cpanel::JSON::XS before version 4.40 for Perl has an integer buffer overflow causing a segfault when parsing crafted JSON, enabling denial-of-service attacks or other unspecified impact
How severe is CVE-2025-40929?: CVE-2025-40929 has a CVSS 3.x base score of 5.6, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2025-40929 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (33rd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-40929?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-40929 have an EU (EUVD) identifier?: Yes. CVE-2025-40929 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-27140.
When was CVE-2025-40929 published?: CVE-2025-40929 was published on 2025-09-08 and last updated on 2026-06-17.

References

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