How severe is CVE-2024-6863?

CVE-2024-6863 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability low.

Is CVE-2024-6863 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (25th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2024-6863?

CVE-2024-6863 affects H2o. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2024-6863?

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

Does CVE-2024-6863 have an EU (EUVD) identifier?

Yes. CVE-2024-6863 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-6964.

When was CVE-2024-6863 published?

CVE-2024-6863 was published on 2025-03-20 and last updated on 2026-06-17.

CVE-2024-6863

CVE-2024-6863 is a medium-severity vulnerability in H2o with a CVSS 3.x base score of 6.5. 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-749.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 0% (25th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-6964
Weakness: CWE-749
Affected product: H2o
Published: 2025-03-20
Last modified: 2026-06-17

Description

In h2oai/h2o-3 version 3.46.0, an endpoint exposing a custom EncryptionTool allows an attacker to encrypt any files on the target server with a key of their choosing. The chosen key can also be overwritten, resulting in ransomware-like behavior. This vulnerability makes it possible for an attacker to encrypt arbitrary files with keys of their choice, making it exceedingly difficult for the target to recover the keys needed for decryption.

Frequently asked questions

What is CVE-2024-6863?: In h2oai/h2o-3 version 3.46.0, an endpoint exposing a custom EncryptionTool allows an attacker to encrypt any files on the target server with a key of their choosing. The chosen key can also be overwritten, resulting in ransomware-like behavior. This vulnerability makes it possible for an attacker to encrypt arbitrary files with keys of their choice, making it exceedingly difficult for the target to recover the keys needed for decryption.
How severe is CVE-2024-6863?: CVE-2024-6863 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability low.
Is CVE-2024-6863 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (25th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-6863?: CVE-2024-6863 affects H2o. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2024-6863?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2024-6863 have an EU (EUVD) identifier?: Yes. CVE-2024-6863 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-6964.
When was CVE-2024-6863 published?: CVE-2024-6863 was published on 2025-03-20 and last updated on 2026-06-17.

References

https://huntr.com/bounties/10f55937-0cba-4530-897f-2abf30ed5270

Affected products (1)

cpe:2.3:a:h2o:h2o:3.46.0:*:*:*:*:*:*:*

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