Vulnerability · Published Jun 1, 2022 · Assigned by GitHub_M

CVE-2022-29169ReDoS on endpoint html5client/useragent in BigBlueButton

High 7.5

In plain English

A high-severity improper input validation in bigbluebutton from bigbluebutton. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.6% (higher than 76% of all known vulnerabilities).

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)1.6%top 24.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

BigBlueButton is an open source web conferencing system. Versions starting with 2.2 and prior to 2.3.19, 2.4.7, and 2.5.0-beta.2 are vulnerable to regular expression denial of service (ReDoS) attacks. By using specific a RegularExpression, an attacker can cause denial of service for the bbb-html5 service. The useragent library performs checking of device by parsing the input of User-Agent header and lets it go through lookupUserAgent() (alias of useragent.lookup() ). This function handles input by regexing and attackers can abuse that by providing some ReDos payload using `SmartWatch`. The maintainers removed `htmlclient/useragent` from versions 2.3.19, 2.4.7, and 2.5.0-beta.2. As a workaround, disable NginX forwarding the requests to the handler according to the directions in the GitHub Security Advisory.

Affected products (as reported)

Vendor	Product	Versions
bigbluebutton	bigbluebutton	>= 2.2, < 2.3.19>= 2.4.0, < 2.4.7>= 2.5-alpha-1, < 2.5.0-beta.2

Weakness: CWE-20 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-rwrv-p665-4vwp x_refsource_CONFIRM
https://github.com/bigbluebutton/bigbluebutton/pull/14886 x_refsource_MISC
https://github.com/bigbluebutton/bigbluebutton/pull/14896 x_refsource_MISC