How severe is CVE-2026-28364?

CVE-2026-28364 has a CVSS 3.x base score of 7.9, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity low, and availability none.

Is CVE-2026-28364 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (11th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-28364?

CVE-2026-28364 affects Ocaml. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-28364?

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

Does CVE-2026-28364 have an EU (EUVD) identifier?

Yes. CVE-2026-28364 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-8988.

When was CVE-2026-28364 published?

CVE-2026-28364 was published on 2026-02-27 and last updated on 2026-06-30.

CVE-2026-28364

CVE-2026-28364 is a high-severity vulnerability in Ocaml with a CVSS 3.x base score of 7.9. 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-126.

Key facts

Severity: High (CVSS 3.x base score 7.9)
EPSS exploit prediction: 0% (11th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-8988
Weakness: CWE-126
Affected product: Ocaml
Published: 2026-02-27
Last modified: 2026-06-30

Description

In OCaml before 4.14.3 and 5.x before 5.4.1, a buffer over-read in Marshal deserialization (runtime/intern.c) enables remote code execution through a multi-phase attack chain. The vulnerability stems from missing bounds validation in the readblock() function, which performs unbounded memcpy() operations using attacker-controlled lengths from crafted Marshal data.

Frequently asked questions

What is CVE-2026-28364?: In OCaml before 4.14.3 and 5.x before 5.4.1, a buffer over-read in Marshal deserialization (runtime/intern.c) enables remote code execution through a multi-phase attack chain. The vulnerability stems from missing bounds validation in the readblock() function, which performs unbounded memcpy() operations using attacker-controlled lengths from crafted Marshal data.
How severe is CVE-2026-28364?: CVE-2026-28364 has a CVSS 3.x base score of 7.9, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity low, and availability none.
Is CVE-2026-28364 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (11th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-28364?: CVE-2026-28364 affects Ocaml. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-28364?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-28364 have an EU (EUVD) identifier?: Yes. CVE-2026-28364 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-8988.
When was CVE-2026-28364 published?: CVE-2026-28364 was published on 2026-02-27 and last updated on 2026-06-30.

References

Affected products (1)

cpe:2.3:a:ocaml:ocaml:*:*:*:*:*:*:*:*

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