CVE-2023-23621
Discourse vulnerable to ReDoS in user agent parsing
Discourse is an open-source discussion platform. Prior to version 3.0.1 on the stable branch and version 3.1.0.beta2 on the beta and tests-passed branches, a malicious user can cause a regular expression denial of service using a carefully crafted user agent. This issue is patched in version 3.0.1 on the stable branch and version 3.1.0.beta2 on the beta and tests-passed branches. There are no known workarounds.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Discourse vulnerable to ReDoS in user agent parsing
Discourse is an open-source discussion platform. Prior to version 3.0.1 on the stable branch and version 3.1.0.beta2 on the beta and tests-passed branches, a malicious user can cause a regular expression denial of service using a carefully crafted user agent. This issue is patched in version 3.0.1 on the stable branch and version 3.1.0.beta2 on the beta and tests-passed branches. There are no known workarounds.
- Record
CVE-2023-23621- CVSS 3.1
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H - Weakness
- CWE-1333
- Updated
- 2026-11-02
EUVDEUVD-2023-27715
Discourse is an open-source discussion platform. Prior to version 3.0.1 on the stable branch and version 3.1.0.beta2 on the beta and tests-passed branches, a malicious user can cause a regular expression denial of service using a carefully crafted user agent. This issue is patched in version 3.0.1 on the stable branch and version 3.1.0.beta2 on the beta and tests-passed branches. There are no known workarounds.
- Record
EUVD-2023-27715- CVSS 3.1
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H - Updated
- 2026-11-02
NVD
Discourse is an open-source discussion platform. Prior to version 3.0.1 on the stable branch and version 3.1.0.beta2 on the beta and tests-passed branches, a malicious user can cause a regular expression denial of service using a carefully crafted user agent. This issue is patched in version 3.0.1 on the stable branch and version 3.1.0.beta2 on the beta and tests-passed branches. There are no known workarounds.
- Record
CVE-2023-23621- CVSS 3.1
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-1333
- Updated
- 2026-11-02
OSV
Discourse vulnerable to ReDoS in user agent parsing
Discourse is an open-source discussion platform. Prior to version 3.0.1 on the stable branch and version 3.1.0.beta2 on the beta and tests-passed branches, a malicious user can cause a regular expression denial of service using a carefully crafted user agent. This issue is patched in version 3.0.1 on the stable branch and version 3.1.0.beta2 on the beta and tests-passed branches. There are no known workarounds.
- Record
CVE-2023-23621- CVSS 3.1
- 8.6 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H - Weakness
- CWE-1333
- Updated
- 2026-11-02
OSVBIT-discourse-2023-23621 No score
Discourse vulnerable to ReDoS in user agent parsing
Discourse is an open-source discussion platform. Prior to version 3.0.1 on the stable branch and version 3.1.0.beta2 on the beta and tests-passed branches, a malicious user can cause a regular expression denial of service using a carefully crafted user agent. This issue is patched in version 3.0.1 on the stable branch and version 3.1.0.beta2 on the beta and tests-passed branches. There are no known workarounds.
- Record
BIT-discourse-2023-23621- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
discourseBitnami |
before 3.0.1 | 3.0.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2023-23621 is a high vulnerability (CVSS 8.6) in Discourse, published January 27, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.89%, the 59th percentile. Fixed in discourse 3.0.1.
References
github.com/discourse/discourse/security/advisories/GHSA-mrfp-54hf-jrcv
nvd.nist.gov/vuln/detail/CVE-2023-23621