Overview
- Description
- Zulip is an open source team chat server. In affected versions Zulip allows organization administrators on a server to configure "linkifiers" that automatically create links from messages that users send, detected via arbitrary regular expressions. Malicious organization administrators could subject the server to a denial-of-service via regular expression complexity attacks; most simply, by configuring a quadratic-time regular expression in a linkifier, and sending messages that exploited it. A regular expression attempted to parse the user-provided regexes to verify that they were safe from ReDoS -- this was both insufficient, as well as _itself_ subject to ReDoS if the organization administrator entered a sufficiently complex invalid regex. Affected users should [upgrade to the just-released Zulip 4.7](https://zulip.readthedocs.io/en/latest/production/upgrade-or-modify.html#upgrading-to-a-release), or [`main`](https://zulip.readthedocs.io/en/latest/production/upgrade-or-modify.html#upgrading-from-a-git-repository).
- Source
- security-advisories@github.com
- NVD status
- Analyzed
Risk scores
CVSS 3.1
- Type
- Primary
- Base score
- 6.5
- Impact score
- 3.6
- Exploitability score
- 2.8
- Vector string
- CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Severity
- MEDIUM
CVSS 2.0
- Type
- Primary
- Base score
- 4
- Impact score
- 2.9
- Exploitability score
- 8
- Vector string
- AV:N/AC:L/Au:S/C:N/I:N/A:P
Social media
- Hype score
- Not currently trending
Configurations
[
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:a:zulip:zulip:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "C12C5D8B-FC65-4A14-B843-106963C0AEA8",
"versionEndExcluding": "4.7"
}
],
"operator": "OR"
}
]
}
]