VulnerabilityModified

CVE-2016-6816

This could be exploited, in conjunction with a proxy that also permitted the invalid characters but with a different interpretation, to inject data into the HTTP response.

EXPLOITHIGH 7.1EPSS 39.6%

Does this matter?

EPSS puts the probability of exploitation in the next 30 days at 39.6%, higher than 99% of all known CVEs. Patch or mitigate before the next change window.

Description

The code in Apache Tomcat 9.0.0.M1 to 9.0.0.M11, 8.5.0 to 8.5.6, 8.0.0.RC1 to 8.0.38, 7.0.0 to 7.0.72, and 6.0.0 to 6.0.47 that parsed the HTTP request line permitted invalid characters. This could be exploited, in conjunction with a proxy that also permitted the invalid characters but with a different interpretation, to inject data into the HTTP response. By manipulating the HTTP response the attacker could poison a web-cache, perform an XSS attack and/or obtain sensitive information from requests other then their own.

CVSS 3.0: 7.1 HIGHCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L
EPSS: 39.63% probability · 99th percentile
Public exploits: 1 in Exploit-DB · first 4 April 2017
CISA KEV: Not listed
Weakness: CWE-20
Affected: apache/tomcat
Source: security@apache.org

EPSS trend

EPSS moved from 47.4% on 21 September 2026 to 39.6% on 27 October 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.

Public exploits (1)

Entries in Exploit-DB that cite this CVE. Links go to the Exploit-DB page and to the file in the public repository; nothing is hosted here. A verified tick means the Exploit-DB team confirmed the exploit works against the stated version.

EDB-ID	Title	Type	Published	Verified
EDB-41783 source ↗	Apache Tomcat 6/7/8/9 - Information Disclosuremultiple · justpentest	remote	4 April 2017	no

References

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