How severe is CVE-2026-45388?

CVE-2026-45388 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2026-45388 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-45388?

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-2026-45388 have an EU (EUVD) identifier?

Yes. CVE-2026-45388 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-36764.

When was CVE-2026-45388 published?

CVE-2026-45388 was published on 2026-06-15 and last updated on 2026-06-17.

CVE-2026-45388

CVE-2026-45388 is a critical-severity vulnerability with a CVSS 3.x base score of 9.1. 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-295.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
EPSS exploit prediction: 0% (13th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-36764
Weakness: CWE-295
Published: 2026-06-15
Last modified: 2026-06-17

Description

In OCaml-TLS before 2.1.0, the client implementation does insufficient checks of the certificate provided by the server, which allows impersonation with certificates that are not meant for server authentication (because of KeyUsage and ExtendedKeyUsage).

Frequently asked questions

What is CVE-2026-45388?: In OCaml-TLS before 2.1.0, the client implementation does insufficient checks of the certificate provided by the server, which allows impersonation with certificates that are not meant for server authentication (because of KeyUsage and ExtendedKeyUsage).
How severe is CVE-2026-45388?: CVE-2026-45388 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2026-45388 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-45388?: 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-2026-45388 have an EU (EUVD) identifier?: Yes. CVE-2026-45388 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-36764.
When was CVE-2026-45388 published?: CVE-2026-45388 was published on 2026-06-15 and last updated on 2026-06-17.

References

https://osv.dev/vulnerability/OSEC-2026-06

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