SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityDeferred

CVE-2025-6507

A vulnerability in the h2oai/h2o-3 repository allows attackers to exploit deserialization of untrusted data, potentially leading to arbitrary code execution and reading of system files.

CRITICAL 9.8EPSS 16.9%

Does this matter?

EPSS puts the probability of exploitation in the next 30 days at 16.9%, higher than 97% of all known CVEs. Patch or mitigate before the next change window.

Description

A vulnerability in the h2oai/h2o-3 repository allows attackers to exploit deserialization of untrusted data, potentially leading to arbitrary code execution and reading of system files. This issue affects the latest master branch version 3.47.0.99999. The vulnerability arises from the ability to bypass regular expression filters intended to prevent malicious parameter injection in JDBC connections. Attackers can manipulate spaces between parameters to evade detection, allowing for unauthorized file access and code execution. The vulnerability is addressed in version 3.46.0.8.

CVSS 3.0
9.8 CRITICALCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
16.94% probability · 97th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-502
Source
security@huntr.dev
EPSS trend
0%10%20%10 October 2026: 15.51%13 October 2026: 16.94%26 October 2026: 16.94%10 October 202626 October 2026

EPSS moved from 15.5% on 10 October 2026 to 16.9% on 26 October 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.