Coturn: Stack buffer overflow in decode_oauth_token_gcm()_CVE-2026-43994

{
    "lastseen": "",
    "description": "Coturn is a free open source implementation of TURN and STUN Server. Versions prior to 4.10.0 contain a stack buffer overflow in decode_oauth_token_gcm(). A uint16_t nonce_len field read from an attacker-supplied OAuth access token (0-65535) is passed directly to memcpy() as the copy length into a 256-byte stack buffer (oauth_encrypted_block.nonce[256]) without bounds checking. The overflow occurs before AES-GCM authentication is verified, the attacker does not need to know the OAuth key or produce a valid AES-GCM token. Up to 735 bytes of attacker-controlled data are written past the buffer, may corrupt adjacent stack data, including control-flow data depending on compiler, ABI, and mitigations. Requires --oauth mode (non-default). This may provide a plausible RCE primitive depending on exploit mitigations; because coturn is widely deployed for WebRTC TURN/STUN and --oauth is commonly recommended, impact can be broad. This issue has been fixed in version 4.10.0.",
    "published": "2026-06-18T19:44:46.575Z",
    "modified": "2026-06-18T19:44:46.575Z",
    "type": "cve",
    "title": "Coturn: Stack buffer overflow in decode_oauth_token_gcm()",
    "source": "GitHub_M",
    "references": "https://github.com/coturn/coturn/security/advisories/GHSA-74pg-rfh2-5qw5\nhttps://github.com/coturn/coturn/releases/tag/4.10.0",
    "id": "CVE-2026-43994",
    "bulletinFamily": "",
    "cwe": [
        "CWE-120"
    ],
    "cvelist": null,
    "sourceData": "coturn coturn < 4.10.0",
    "sourceHref": "",
    "cvss": {
        "score": 8.1,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
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        "baseScore": 0,
        "baseSeverity": "",
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        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
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            "baseScore": 0,
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    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "coturn",
    "version": "< 4.10.0",
    "vendor": "coturn",
    "ai_description": "",
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    "ai_score": 0
}