CVE-2026-8752: A weakness has been identified in h2oai h2o-3 up to 7402

Q: How do I fix CVE-2026-8752?

h2o: upgrade to newer than 7402. Exact commands for each OS are on this page.

Q: Is CVE-2026-8752 being exploited?

CVE-2026-8752 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-8752 affect?

CVE-2026-8752 affects h2o. Severity is medium (CVSS 5.3). A weakness has been identified in h2oai h2o-3 up to 7402. This vulnerability affects the function exec of the file h2o-core/src/main/java/water/rapids/ast/prims/misc/AstSetProperty.java of the component Rapids setproperty Primitive Handler.

Q: How urgent is CVE-2026-8752?

Priority 29/100. Remotely exploitable, no login, no user action

Routine

MEDIUM 5.3REMOTEUPGRADE

CVE-2026-8752 is a medium-severity flaw (CVSS 5.3) affecting h2o. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A weakness has been identified in h2oai h2o-3 up to 7402. This vulnerability affects the function exec of the file h2o-core/src/main/java/water/rapids/ast/prims/misc/AstSetProperty.java of the component Rapids setproperty Primitive Handler. Executing a manipulation can lead to improper access controls. The attack may be performed from remote. The exploit has been made available to the public and could be used for attacks. The vendor was contacted

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 76%)
CISA exploited list	No
Weakness	CWE-266, CWE-284
Published	2026-05-17
Last modified	2026-10-14

Publisher (CNA): VulDB · Vendor: h2o

Last updated 2026-10-14 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-17 12:16 UTCPublished CVE record published
2026-10-14 20:10 UTCUpdated Record last modified

h2o h2o UPGRADE

Affected: <= 7402

Fixed in: newer than 7402

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy h2o || rpm -q h2o || h2o --version

2. UPGRADE to newer than 7402 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade h2o

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade h2o

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-8752?

h2o: upgrade to newer than 7402. Exact commands for each OS are on this page.

Is CVE-2026-8752 being exploited?

CVE-2026-8752 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-8752 affect?

CVE-2026-8752 affects h2o. Severity is medium (CVSS 5.3). A weakness has been identified in h2oai h2o-3 up to 7402. This vulnerability affects the function exec of the file h2o-core/src/main/java/water/rapids/ast/prims/misc/AstSetProperty.java of the component Rapids setproperty Primitive Handler.

How urgent is CVE-2026-8752?

Priority 29/100. Remotely exploitable, no login, no user action

Software pages

Java vulnerabilities

Related CVEs

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CVE-2026-8751 HIGH 7.3 UPGRADE A security flaw has been discovered in h2oai h2o-3 up to 7402
CVE-2026-8750 MEDIUM 5.3 UPGRADE A vulnerability was identified in h2oai h2o-3 up to 7402
CVE-2026-44452 MEDIUM 5.9 UPGRADE h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3
CVE-2026-44453 HIGH 7.5 UPGRADE h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3

References

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