Joomla! CMS: Improper Neutralization of CRLF Sequences
CVE-2026-71573 is a high-severity improper neutralization of CRLF sequences vulnerability in Joomla! CMS from Joomla! Project, with a CVSS 3.1 base score of 8.3 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Joomla! CMS versions: 4.0.0-5.4.6; 6.0.0-6.1.2. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.34% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Joomla! to 5.4.8 or 6.1.3, whichever matches your release line, or a later version.
- 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 |
|---|---|---|---|
| Joomla! Project | Joomla! CMS | 4.0.0-5.4.6; 6.0.0-6.1.2 | Not stated |
| Joomla | Joomla! | 4.0.0 up to, but not including, 5.4.8; 6.0.0 up to, but not including, 6.1.3 | 5.4.8, 6.1.3 |
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
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- LowSome restricted data can be read.
- Integrity
- LowLimited modification of data is possible.
- Availability
- LowPerformance or availability is reduced.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 6.9 | Medium | CNA (joomla.org) |
| CVSS 3.1 | 8.3 | High | NVD |
Official description
Joomla! Core - [20260802] - Improper CORS origin validation in Joomla 4.0.0-5.4.7, 6.0.0-6.1.2 - An improper implementation prevented configured CORS origins from being properly validated in CORS requests.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of CRLF Sequences
The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.
How developers prevent this class of flaw
- Appropriately filter or quote CRLF sequences in user-controlled input.
More Improper Neutralization of CRLF Sequences vulnerabilities (CWE-93)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other references
- joomla.org/Product
Other vulnerabilities in Joomla! CMS
- 7.5 High severity
- 8.0 High severity
- 8.3 High severity
- 9.8 Critical severity
- 7.5 High severity
Recent Improper Neutralization of CRLF Sequences vulnerabilities
- 9.8 Critical severity
- 9.9 Critical severity
- 9.1 Critical severity
- 7.2 High severity
- 7.6 High severity
- 8.8 High severity
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