CVE-2021-41186 ReDoS vulnerability in parser_apache2

2021-10-2913:40:10

CWE-400

GitHub_M

www.cve.org

5.9 Medium

CVSS3

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

0.001 Low

EPSS

Percentile

47.3%

JSON

Fluentd collects events from various data sources and writes them to files to help unify logging infrastructure. The parser_apache2 plugin in Fluentd v0.14.14 to v1.14.1 suffers from a regular expression denial of service (ReDoS) vulnerability. A broken apache log with a certain pattern of string can spend too much time in a regular expression, resulting in the potential for a DoS attack. This issue is patched in version 1.14.2 There are two workarounds available. Either don’t use parser_apache2 for parsing logs (which cannot guarantee generated by Apache), or put patched version of parser_apache2.rb into /etc/fluent/plugin directory (or any other directories specified by the environment variable FLUENT_PLUGIN or --plugin option of fluentd).

CNA Affected

[
  {
    "product": "fluentd",
    "vendor": "fluent",
    "versions": [
      {
        "status": "affected",
        "version": ">= 0.14.14, < 1.14.2"
      }
    ]
  }
]