CVE-2021-32763
Regular Expression Denial of Service in OpenProject forum messages
OpenProject is open-source, web-based project management software. In versions prior to 11.3.3, the MessagesController class of OpenProject has a quote method that implements the logic behind the Quote button in the discussion forums, and it uses a regex to strip <pre> tags from the message being quoted. The (.|\s) part can match a space character in two ways, so an unterminated <pre> tag containing n spaces causes Ruby's regex engine to backtrack to try 2<sup>n</sup> states in the NFA. This will result in a Regular Expression Denial of Service. The issue is fixed in OpenProject 11.3.3. As a workaround, one may install the patch manually.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
Regular Expression Denial of Service in OpenProject forum messages
OpenProject is open-source, web-based project management software. In versions prior to 11.3.3, the MessagesController class of OpenProject has a quote method that implements the logic behind the Quote button in the discussion forums, and it uses a regex to strip <pre> tags from the message being quoted. The (.|\s) part can match a space character in two ways, so an unterminated <pre> tag containing n spaces causes Ruby's regex engine to backtrack to try 2<sup>n</sup> states in the NFA. This will result in a Regular Expression Denial of Service. The issue is fixed in OpenProject 11.3.3. As a workaround, one may install the patch manually.
- Record
CVE-2021-32763- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-400
- Updated
- 2026-11-02
EUVDEUVD-2021-19531
OpenProject is open-source, web-based project management software. In versions prior to 11.3.3, the MessagesController class of OpenProject has a quote method that implements the logic behind the Quote button in the discussion forums, and it uses a regex to strip <pre> tags from the message being quoted. The (.|\s) part can match a space character in two ways, so an unterminated <pre> tag containing n spaces causes Ruby's regex engine to backtrack to try 2<sup>n</sup> states in the NFA. This will result in a Regular Expression Denial of Service. The issue is fixed in OpenProject 11.3.3. As a workaround, one may install the patch manually.
- Record
EUVD-2021-19531- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L - Updated
- 2026-11-03
NVD
OpenProject is open-source, web-based project management software. In versions prior to 11.3.3, the MessagesController class of OpenProject has a quote method that implements the logic behind the Quote button in the discussion forums, and it uses a regex to strip <pre> tags from the message being quoted. The (.|\s) part can match a space character in two ways, so an unterminated <pre> tag containing n spaces causes Ruby's regex engine to backtrack to try 2<sup>n</sup> states in the NFA. This will result in a Regular Expression Denial of Service. The issue is fixed in OpenProject 11.3.3. As a workaround, one may install the patch manually.
- Record
CVE-2021-32763- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L - CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 4.0 Medium
AV:N/AC:L/Au:S/C:N/I:N/A:P - Weakness
- CWE-400
- Updated
- 2026-11-02
OSV
OpenProject is open-source, web-based project management software. In versions prior to 11.3.3, the MessagesController class of OpenProject has a quote method that implements the logic behind the Quote button in the discussion forums, and it uses a regex to strip <pre> tags from the message being quoted. The (.|\s) part can match a space character in two ways, so an unterminated <pre> tag containing n spaces causes Ruby's regex engine to backtrack to try 2<sup>n</sup> states in the NFA. This will result in a Regular Expression Denial of Service. The issue is fixed in OpenProject 11.3.3. As a workaround, one may install the patch manually.
- Record
CVE-2021-32763- CVSS 3.1
- 6.5 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-32763 is a medium vulnerability (CVSS 4.3) in Openproject, published July 20, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.92%, the 60th percentile. No source names a fixed version.