CVE-2016-4864 json
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 spe…
published 2017-05-12 9 y ago modified 2026-06-17 4 mo ago also EUVD-2016-5844
- cvss
- 7.5
- version 3.0, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.8%
- EPSS 1.8% chance of exploitation in 30 days, percentile 78%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- github.com/h2o/h2o/issues/1077 advisory
Exploit prediction
1.80% chance of exploitation in the next 30 days, higher than 78% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.0 | 7.5 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVD | 2.0 | 5.0 | AV:N/AC:L/Au:N/C:N/I:N/A:P |
Affected products
- Kazuho Oku H2O
Classification
- Weakness
-
- CWE-134 Use of Externally-Controlled Format String
References
-
github.com
/h2o/h2o/issues/1077
patch, third-party-advisory
-
jvn.jp
/en/jp/JVN94779084/index.html
third-party-advisory, vdb-entry
Sources
- CVE List CVE-2016-4864
- NVD CVE-2016-4864
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.