Apache Tapestry: Inefficient Regular Expression Complexity
CVE-2022-31781 is a high-severity inefficient regular expression complexity vulnerability in Apache Tapestry from Apache, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 5.8.1 as the first without the flaw, so updating Apache Tapestry to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 1.97% chance of exploitation within 30 days, higher than 81% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Apache Tapestry to 5.8.1 or a later version.
- Update Tapestry to 5.8.2 or a later version.
- Read the advisory on openwall.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Apache | Apache Tapestry | 5.8.1 up to, but not including, 5.8.1 | 5.8.1 |
| Apache | Tapestry | before 5.8.2 | 5.8.2 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.
Official description
Apache Tapestry up to version 5.8.1 is vulnerable to Regular Expression Denial of Service (ReDoS) in the way it handles Content Types. Specially crafted Content Types may cause catastrophic backtracking, taking exponential time to complete. Specifically, this is about the regular expression used on the parameter of the org.apache.tapestry5.http.ContentType class. Apache Tapestry 5.8.2 has a fix for this vulnerability. Notice the vulnerability cannot be triggered by web requests in Tapestry code alone. It would only happen if there's some non-Tapestry codepath passing some outside input to the ContentType class constructor.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Inefficient Regular Expression Complexity
The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.
How developers prevent this class of flaw
- Use regular expressions that do not support backtracking, e.g. by removing nested quantifiers.
- Set backtracking limits in the configuration of the regular expression implementation, such as PHP's pcre.backtrack_limit. Also consider limits on execution time for the process.
- Do not use regular expressions with untrusted input. If regular expressions must be used, avoid using backtracking in the expression.
More Inefficient Regular Expression Complexity vulnerabilities (CWE-1333)
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Advisories
- openwall.com/lists/oss-security/2022/07/12/3Mailing List
Other vulnerabilities in Apache Tapestry
- 7.5 High severity
- 9.8 Critical severity
Recent Inefficient Regular Expression Complexity vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
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