CVE Intelligence
High

CVE-2026-71573 — Joomla! Core - [20260802] - Improper CORS origin validation in Joomla 4.0.0-5.4.7…

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.

Published Aug 18, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database · CNA: security@joomla.org

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
—
No EPSS score.
Affects
Joomla
Joomla!
CVSS base
8.3
High · 2 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Joomla Joomla!).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Joomla Joomla! ≥ 4.0.0 and < 5.4.8≥ 6.0.0 and < 6.1.3 Vulnerable NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
Low

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
6.9 CVSS 4.0 Medium — — security@joomla.org via NIST National Vulnerability Database
8.3 CVSS 3.1 High 3.9 3.7 nvd@nist.gov via NIST National Vulnerability Database
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-93

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

  • 2026
  • Record published
    Oct 15, 2026
  • CVSS changed · 8.3
    Oct 15, 2026 · NIST National Vulnerability Database
  • Source status changed · → Analyzed
    Oct 15, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 15, 2026 · NIST National Vulnerability Database
  • CVE published
    Aug 18, 2026 · security@joomla.org

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

2 on the record

Elsewhere on this site

Joomla
every CVE for this vendor
CWE-93
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-92232 Joomla! Core - [20260916] - Core - XSS filter bypass in InputFilter via whitespace characters in HTML data URIs in Joomla 1.5.0-5.4.8, 6.0.0-6.1.3 16d
  • CVE-2026-92222 Joomla! Core - [20260909] - Core - SSRF vectors in various core extensions in Joomla 4.0.0-5.4.8, 6.0.0-6.1.3 16d
  • CVE-2026-92226 Joomla! Core - [20260913] - Core - Improper ACL checks for varous webservice edit tasks in Joomla 4.0.0-5.4.8, 6.0.0-6.1.3 16d
  • CVE-2026-92223 Joomla! Core - [20260910] - Core - Improper ACL checks for workflow stage changes in Joomla 5.0.0-5.4.8, 6.0.0-6.1.3 16d
  • CVE-2026-92224 Joomla! Core - [20260911] - Core - XSS in link toolbar layout in Joomla 4.0.0-5.4.8, 6.0.0-6.1.3 16d
  • CVE-2026-92225 Joomla! Core - [20260912] - Core - XSS in module list in Joomla 4.0.0-5.4.8, 6.0.0-6.1.3 16d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No FIRST EPSS score.
  • No fixed version, patch or mitigation documented.
  • No CISA SSVC assessment.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-71573 is "Joomla! Core - [20260802] - Improper CORS origin validation in Joomla 4.0.0-5.4.7…", rated High. It affects Joomla! (Joomla); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 8.3 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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