What’s Vulnerable › Vulnerabilities

CVE-2021-33580: regex injection leading to DoS

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-08-18 · updated 2026-06-17
• Weakness: CWE-400

Description

User controlled `request.getHeader("Referer")`, `request.getRequestURL()` and `request.getQueryString()` are used to build and run a regex expression. The attacker doesn't have to use a browser and may send a specially crafted Referer header programmatically. Since the attacker controls the string and the regex pattern he may cause a ReDoS by regex catastrophic backtracking on the server side. This problem has been fixed in Roller 6.0.2.

Affected products

• Apache Software Foundation Apache Roller: before 6.0.2 — fixed in 6.0.2

How to fix

Upgrade to a fixed version: Apache Software Foundation Apache Roller 6.0.2. Check the vendor advisory for mitigations.

References

• http://www.openwall.com/lists/oss-security/2021/08/18/1
• https://lists.apache.org/thread.html/r9d967d80af941717573e531db2c7353a90bfd0886e9b5d5d79f75506%40%3Cuser.roller.apache.org%3E
• http://www.openwall.com/lists/oss-security/2021/08/18/1
• https://lists.apache.org/thread.html/r9d967d80af941717573e531db2c7353a90bfd0886e9b5d5d79f75506%40%3Cuser.roller.apache.org%3E

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