CVE-2026-48939
About
A vulnerability in the iCagenda extension for Joomla allows the upload of arbitrary files in the file attachment feature, ultimately resulting in PHP code upload and execution.
Rainforest analyst review
The iCagenda extension for Joomla accepts files through its event attachment feature without restricting their type, so where the application expects a document an attacker can upload a PHP file instead. Because the file lands in a web-served location, requesting it causes the server to execute it, giving the attacker code execution in the context of the Joomla site — the classic unrestricted-upload-to-web-shell path.
Third-party Joomla extensions are a perennial soft spot: the CMS core may be diligently patched while an add-on like iCagenda is forgotten, and these sites are public web servers. A web shell here is full compromise of the site and a foothold for defacement, spam distribution, credential theft, or pivoting deeper. Update or remove the iCagenda extension, configure the upload directories so PHP cannot execute from them, and inspect the attachment paths for already-planted scripts, since an exposed site may have been hit before the fix was applied.
References
- https://www.icagenda.com/
- https://github.com/Polosss/By-Poloss..-..CVE-2026-48939
- https://mysites.guru/blog/icagenda-zero-day-file-upload-rce/
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-48939
- https://www.icagenda.com/docs/changelog/icagenda-3-9-15
- https://www.icagenda.com/docs/changelog/icagenda-4-0-8
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Frequently asked questions
What is CVE-2026-48939?
A vulnerability in the iCagenda extension for Joomla allows the upload of arbitrary files in the file attachment feature, ultimately resulting in PHP code upload and execution.
How severe is CVE-2026-48939?
CVE-2026-48939 carries a CVSS 3.1 base score of 9.8, rated critical. On the Rainforest Risk Index — which weighs the severity alongside how easy the flaw is to reach and how broad its impact is — it scores 99 out of 100, in the critical band.
How is CVE-2026-48939 exploited?
According to the CVSS vector (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H): attack vector Network, attack complexity Low, privileges required None, user interaction None. Impact on confidentiality High, integrity High and availability High.
Which products are affected by CVE-2026-48939?
Public advisories list the following as affected: icagenda. Check the references on this page for the exact versions each vendor confirms.
How do I fix CVE-2026-48939?
Apply the fix the vendor published — the references on this page link to the primary advisories and patches. When patching can't happen right away, reduce the exposure of the affected component and watch it for exploitation attempts. Rainforest customers see this vulnerability correlated to their own assets and prioritized by real exposure, not by score alone.
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