CVE-2016-4864 Denial of service in H2O

What is CVE-2016-4864?

CVE-2016-4864 is a high-severity denial of service vulnerability in Kazuho Oku H2O, published on 12 May 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

H2O versions 2.0.3 and earlier and 2.1.0-beta2 and earlier allows remote attackers to cause a denial-of-service (DoS) via format string specifiers in a template file via fastcgi, mruby, proxy, redirect or reproxy.

Weakness: CWE-134

Which versions are affected by CVE-2016-4864?

It affects 1 product.

Products include Dena H2o.

How do I fix CVE-2016-4864?

No fix has been published for CVE-2016-4864 yet. Limit exposure of the affected software until one is available.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2016-4864 being exploited?

There is no known exploitation of CVE-2016-4864 in the wild and no public exploit code.

Other vulnerabilities in Kazuho Oku H2O

• CVE-2018-0608 Memory corruption in H2O Critical 9.8
• CVE-2016-7835 Use after free in H2O Critical 9.1
• CVE-2023-30847 H2O vulnerable to read from uninitialized pointer in the reverse proxy handler High 8.2
• CVE-2017-10868 Denial of service in H2O High 7.5
• CVE-2017-10869 Memory corruption in H2O High 7.5

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-h4xp-827w-ffh7.