How severe is CVE-2026-4746?

CVE-2026-4746 has a CVSS 4.0 base score of 10.0, rated critical severity.

Is CVE-2026-4746 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (19th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-4746?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-4746 have an EU (EUVD) identifier?

Yes. CVE-2026-4746 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-14745.

When was CVE-2026-4746 published?

CVE-2026-4746 was published on 2026-03-24 and last updated on 2026-06-17.

CVE-2026-4746

CVE-2026-4746 is a critical-severity vulnerability with a CVSS 4.0 base score of 10.0. 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-787.

Key facts

Severity: Critical (CVSS 4.0 base score 10.0)
EPSS exploit prediction: 0% (19th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-14745
Weakness: CWE-787
Published: 2026-03-24
Last modified: 2026-06-17

Description

Out-of-bounds Write vulnerability in timeplus-io proton (base/poco/Foundation/src‎ modules). This vulnerability is associated with program files inflate.C. This issue affects proton: before 1.6.16.

Frequently asked questions

What is CVE-2026-4746?: Out-of-bounds Write vulnerability in timeplus-io proton (base/poco/Foundation/src‎ modules). This vulnerability is associated with program files inflate.C. This issue affects proton: before 1.6.16.
How severe is CVE-2026-4746?: CVE-2026-4746 has a CVSS 4.0 base score of 10.0, rated critical severity.
Is CVE-2026-4746 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (19th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-4746?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-4746 have an EU (EUVD) identifier?: Yes. CVE-2026-4746 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-14745.
When was CVE-2026-4746 published?: CVE-2026-4746 was published on 2026-03-24 and last updated on 2026-06-17.

References

https://github.com/timeplus-io/proton/pull/943

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