7.5

CVE-2016-4817: dena h2o

Modified
Published 19-06-2016Last modified 06-08-2024

Vulnerability summary

CVE-2016-4817 is a high (CVSS 7.5) vulnerability in dena h2o. EPSS estimates a 4.45% chance of exploitation in the next 30 days, higher than 91.4% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 7.5 (NVD); no exploitation reported by the 5 checked sources; EPSS 4% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
7.5/10
010
High · v3.0 (NVD)
EPSS score
4.45%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 19-06-2016
    PublishedVulnerability first disclosed.
  2. 06-08-2024
    Last modifiedVulnerability information updated.

Description

lib/http2/connection.c in H2O before 1.7.3 and 2.x before 2.0.0-beta5 mishandles HTTP/2 disconnection, which allows remote attackers to cause a denial of service (use-after-free and application crash) or possibly execute arbitrary code via a crafted packet.

CVSS metrics

2 scores · 1 source · 2 versions

EPSS trend

Probability

4.45%

Chance of exploitation in the next 30 days

Percentile

91%

Versus all other CVEs

30-day change

No change 0.00 pp

From 4.45% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Dena1 product
  • h2o≤ 1.7.2 | ≤ 2.0.0

1 vendor · 1 product

References

4 links