SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2016-6817

This made a denial of service attack possible.

HIGH 7.5EPSS 7.19%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (7.19%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

The HTTP/2 header parser in Apache Tomcat 9.0.0.M1 to 9.0.0.M11 and 8.5.0 to 8.5.6 entered an infinite loop if a header was received that was larger than the available buffer. This made a denial of service attack possible.

CVSS 3.1
7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
7.19% probability · 94th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-119, CWE-835
Affected
apache/tomcat
Source
security@apache.org
EPSS trend
0%5%10%27 October 2026: 7.19%27 October 202627 October 2026

EPSS 7.2% since 27 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.