NVD / CVE Program· CNA GitHub_M

CVE-2021-32763: Regular Expression Denial of Service in OpenProject forum messages

Noroxi assessment

Priority: Monitor (action score 26/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.92% (FIRST EPSS); higher than 60.4% of all records.
Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
No fixed version is recorded, but the references include a patch (commit or PR) link.
Severity is disputed: the assigning authority (CNA) scores it 4.3, NVD 6.5.

Low priority for now. See the fix and affected versions sections below.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 6.5 · v3.1—No exploit No fix recorded

Denial of service

Published: Jul 20, 2021
Updated: Jun 16, 2026
EPSS: 0.9% · 60th percentile
CWE: CWE-400

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 26 / 40 · 6.5 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.9%

CNA vs NVD score

NVD: 6.5
CNA · GitHub_M: 4.3; 2.2 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
No fixed version yet

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
openproject	openproject	cpe:2.3:a:openproject:openproject

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

openproject openprojectbefore 11.3.3

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

opf openproject
- < 11.3.3affected

Same product

openproject: all records

Other highest-scoring records for the same primary product.

CVE-2019-11600A SQL injection vulnerability in the activities API in OpenProject before 8.3.2 allows a remote attacker to execute arbitrary SQL commands v
56Plan
CVE-2026-25763Command Injection on OpenProject repositories leads to Remote Code Execution
37Monitor
CVE-2026-24685OpenProject has Argument Injection on Repository module that allows Arbitrary File Write
37Monitor

Published before and after this one in the same product

← EarlierCVE-2017-11667Jul 26, 2017 · OpenProject before 6.1.6 and 7.x before 7.0.3 mishandles session expiry, which allows remote attackers to perform APIv3 requests indefinitel
32Monitor
← EarlierCVE-2019-17092Oct 9, 2019 · An XSS vulnerability in project list in OpenProject before 9.0.4 and 10.x before 10.0.2 allows remote attackers to inject arbitrary web scri
24Monitor
Later →CVE-2021-43830Dec 14, 2021 · SQL injection in OpenProject
35Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

opf/openprojectPR 9447.patch

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: none
Integrity: none
Availability: high · the service can be disrupted

Attack vector: Network
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality impact: None
Integrity impact: None
Availability impact: High

Weakness class (CWE)

CWE-400 · Uncontrolled Resource Consumption

CVSS vector

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

nvd-primary

Root cause

Code that parses nested structures sets no depth or size limit. A small input can turn into a disproportionate processing load.

The bug in code

The whole CWE-400 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1function expand(node) {
2  return node.children.map(expand);
3}

Fixed

1const MAX_DEPTH = 32;
2function expand(node, depth = 0) {
3  if (depth > MAX_DEPTH) throw new Error("too deep");
4  return node.children.map((c) => expand(c, depth + 1));
5}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

Endpoint Denial of ServiceT1499

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

github.com/opf/openproject/pull/9447.patch

Show all references (1 more)

github.com/opf/openproject/security/advisories/GHSA-qqvp-j6gm-q56f

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records