CVE-2026-41309: Open Source Social Network (OSSN) is open-source social networking software developed in PHP. Versions prior to 9.0 are vulnerable to resource exhaust...

Description

Open Source Social Network (OSSN) is open-source social networking software developed in PHP. Versions prior to 9.0 are vulnerable to resource exhaustion. An attacker can upload a specially crafted image with extreme pixel dimensions (e.g., $10000 \times 10000$ pixels). While the compressed file size on disk may be small, the server attempts to allocate significant memory and CPU cycles during the decompression and resizing process, leading to a Denial of Service (DoS) condition. It is highly recommended to upgrade to OSSN 9.0. This version introduces stricter validation of image dimensions and improved resource management during the processing phase. Those who cannot upgrade immediately can mitigate the risk by adjusting their `php.ini` settings to strictly limit `memory_limit` and `max_execution_time` and/or implementing a client-side and server-side check on image headers to reject files exceeding reasonable pixel dimensions (e.g., $4000 \times 4000$ pixels) before processing begins.

Metrics

CVSS 3.1

8.2/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H

EPSS Probability

0.37%

28.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

References

Timeline

Published: Apr 24, 2026
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2026-41309?

Open Source Social Network (OSSN) is open-source social networking software developed in PHP. Versions prior to 9.0 are vulnerable to resource exhaustion. An attacker can upload a specially crafted image with extreme pixel dimensions (e.g., $10000 \times 10000$ pixels). While the compressed file size on disk may be small, the server attempts to allocate significant memory and CPU cycles during the decompression and resizing process, leading to a Denial of Service (DoS) condition. It is highly recommended to upgrade to OSSN 9.0. This version introduces stricter validation of image dimensions and improved resource management during the processing phase. Those who cannot upgrade immediately can mitigate the risk by adjusting their `php.ini` settings to strictly limit `memory_limit` and `max_execution_time` and/or implementing a client-side and server-side check on image headers to reject files exceeding reasonable pixel dimensions (e.g., $4000 \times 4000$ pixels) before processing begins.

How severe is CVE-2026-41309?

CVE-2026-41309 has a CVSS score of 8.2/10 (HIGH severity). The EPSS model estimates a 0.37% probability of exploitation in the next 30 days.

How do I fix CVE-2026-41309?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.