Exploitation timeline
Threadlinqs has recorded 6 h2o CVEs published between and . The busiest month was 2026-07 (6 new CVEs). None of them is listed in CISA KEV yet.
Most exploited vulnerabilities
Ranked with CISA KEV listings first, then EPSS exploit probability, then CVSS score. Showing 6 of 6 tracked h2o CVEs.
- CVE-2026-44435high 7.5EPSS 0.3%
- CVE-2026-44436high 7.5EPSS 0.3%
- CVE-2026-44452medium 5.9EPSS 0.3%
- CVE-2026-44453high 7.5
- CVE-2026-44433medium 5.3
- CVE-2026-44434medium 5.3
Products affected
Threadlinqs normalises CPE and CNA product records across all 6 CVEs; 2 distinct h2o products are affected. The most frequently affected:
- quicly 4 CVEs
- h2o 2 CVEs
Threat activity
No tracked threat campaign references h2o products or CVEs yet. Vulnerability records are still monitored for exploitation and linked as campaigns are ingested.
How to prioritise h2o patching
This order follows the data Threadlinqs holds for h2o, not a generic severity checklist:
- No h2o CVE is in CISA KEV yet, so rank by exploit probability instead.
- Outside KEV, the highest EPSS scores are CVE-2026-44435 (0.3%), CVE-2026-44436 (0.3%), CVE-2026-44452 (0.3%).
- 0 CVEs score Critical and 3 High on CVSS v3 (maximum 7.5, average 6.5); sequence these after KEV and high-EPSS items.
About this data
Vendor attribution comes from the CNA and CPE product records of each CVE, folded to one vendor name; CVSS, EPSS and KEV status are read from the Threadlinqs CVE catalog; campaign and actor links come from tracked threat records. Counts reflect the data as of 2026-10-05 and refresh daily.