Affected versions: ≥ 12.2.9 and < 16.0.0
Full advisory: regularlabs.com
CVE-2026-74253CriticalPublished 17 August 2026
Sourcerer (sourcerer) 12.2.9 to below 16.0.0 - Unauthenticated Remote Code Execution
Regular Labs Sourcerer before 16.0.0 processes {source} blocks found in Joomla's final rendered HTML without reliably determining where that code originated, allowing an unauthenticated visitor to get PHP executed on the site. CVE-2026-74253, CVSS 4.0 10.0 Critical (AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H), CWE-94, credited to Lukasz Rybak. THIS FLAW TOOK THREE ATTEMPTS TO FIX AND IS BEING EXPLOITED IN THE WILD. The vendor first patched it in 14.0.0 (17 August 2026) and the Joomla CNA originally titled the record "Sourcerer < 14.0.0", but that patch was incomplete. 15.0.0 (24 August 2026) reworked the permission model and still did not close it. Only 16.0.0 (26 August 2026) carries the vendor's second [SECURITY FIX] entry: "Prevents unverified Sourcerer code from executing when an untrusted user supplies Sourcerer syntax through URL or form names and values, raw request bodies, uploads, cookies or request headers." The CNA has re-scoped the same CVE id accordingly and its affected range now reads 1.0.0 to 15.0.0, so 14.0.0, 14.0.1 and 15.0.0 are vulnerable despite each having been published as a fix. The Joomla Security Strike Team confirmed on 24 August 2026 that this is being actively exploited in the wild, from around 19 August 2026, which is after the incomplete 14.0.0 patch shipped. UPDATE TO 16.0.0 OR LATER. Updating to 14.x or 15.0.0 is not sufficient. If you cannot update immediately, disable the Sourcerer system plugin, which is the plugin that renders Sourcerer tags. Note that 16.0.0 is deliberately a BC break: it blocks common filesystem-write functions by default and adds them to existing saved settings, so trusted Sourcerer PHP that writes files may stop working, and Pro gains a Trusted Request User Groups setting controlling which logged-in users may submit Sourcerer tags through website requests. Pro builds report their version with a PRO suffix (15.0.0PRO); the matcher strips that suffix before comparison, so this rule is bounded below the fixed version in the normal way and a site on 16.0.0PRO is correctly not flagged.
Affected versions: ≥ 12.2.9 and < 16.0.0
Official record: cve.org · NVD
Every connected Joomla site is checked against these rules on each audit, and flagged if it runs an affected version.
Affected extensions and versions
Sourcerer - Sourcerer (sourcerer) below 13.0.0 - Code Execution (CVE-2025-22204) and PHP/Script Privilege Escalation
Regular Labs Sourcerer is affected by two lines of security issue. (1) CVE-2025-22204: improper control of code generation leading to code execution in versions before 11.0.0. (2) The coordinated Regular Labs security release of 22 July 2026 (Sourcerer 13.0.0) restricts PHP in articles to content created and last modified by Super Users, enforces the configured CSS/JavaScript/PHP permissions across tags, attributes, files and both article creators and modifiers, restricts PHP includes to the configured include folder, and fixes script/style security checks that missed executable tag variants - collectively a set of privilege-escalation and code/markup-execution hardening fixes. No CVE was assigned to the 22 July issues. Update to Sourcerer 13.0.0 or later. Note: 13.0.0 preserves your existing Pro security settings on update, so review them to opt into the new stricter defaults. CVE ids assigned by the Joomla CNA for this extension in the 22 July 2026 Regular Labs security release: CVE-2026-64796. Sites on this version range are ALSO within the affected range of CVE-2026-74253 (Sourcerer before 16.0.0, CVSS 4.0 10.0 Critical, unauthenticated remote code execution through unverified reflected code, CWE-94, credited to Lukasz Rybak), whose CNA record was re-scoped on 26 August 2026 and now covers 1.0.0 to 15.0.0. Updating to 13.0.0 is therefore no longer sufficient, and neither is 14.x or 15.0.0: the vendor fix for CVE-2026-74253 was incomplete twice and only Sourcerer 16.0.0 (26 August 2026) resolves it. Update to 16.0.0 or later. The Joomla Security Strike Team confirmed active exploitation in the wild from around 19 August 2026. If you cannot update immediately, disable the Sourcerer system plugin, which is the plugin that renders Sourcerer tags.
Affected versions: ≤ 12.2.8
Full advisory: regularlabs.com
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Rules current as of 14 September 2026.