pppoe: drop PFC frames_CVE-2026-53003

{
    "lastseen": "",
    "description": "In the Linux kernel, the following vulnerability has been resolved:\n\npppoe: drop PFC frames\n\nRFC 2516 Section 7 states that Protocol Field Compression (PFC) is NOT\nRECOMMENDED for PPPoE. In practice, pppd does not support negotiating\nPFC for PPPoE sessions, and the current PPPoE driver assumes an\nuncompressed (2-byte) protocol field. However, the generic PPP layer\nfunction ppp_input() is not aware of the negotiation result, and still\naccepts PFC frames.\n\nIf a peer with a broken implementation or an attacker sends a frame with\na compressed (1-byte) protocol field, the subsequent PPP payload is\nshifted by one byte. This causes the network header to be 4-byte\nmisaligned, which may trigger unaligned access exceptions on some\narchitectures.\n\nTo reduce the attack surface, drop PPPoE PFC frames. Introduce\nppp_skb_is_compressed_proto() helper function to be used in both\nppp_generic.c and pppoe.c to avoid open-coding.",
    "published": "2026-06-24T16:29:15.268Z",
    "modified": "2026-06-28T06:37:53.970Z",
    "type": "cve",
    "title": "pppoe: drop PFC frames",
    "source": "Linux",
    "references": "https://git.kernel.org/stable/c/cb3beef35ab5e0c1afca9fd7648c6ae499786377\nhttps://git.kernel.org/stable/c/ba758fdf1399f310b30098b6faa3fd043de47dd2\nhttps://git.kernel.org/stable/c/fcca1df05322bb04e344dd1178b54b76a08eb7c3\nhttps://git.kernel.org/stable/c/8a5e840babc5c0fbd10c73728a13192347771ec6\nhttps://git.kernel.org/stable/c/49e41b60ccd1bdbe9e218420f716dd5f9a2f9c71\nhttps://git.kernel.org/stable/c/0cab5d077dd1efd2bd1a47271acc35894f945b4f\nhttps://git.kernel.org/stable/c/2b5c3c040d020e3ab3b9a8887031202d96843b1e\nhttps://git.kernel.org/stable/c/cc1ff87bce1ccd38410ab10960f576dcd17db679",
    "id": "CVE-2026-53003",
    "bulletinFamily": "",
    "cwe": null,
    "cvelist": null,
    "sourceData": "Linux Linux 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6\nLinux Linux 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6\nLinux Linux 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6\nLinux Linux 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6\nLinux Linux 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6\nLinux Linux 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6\nLinux Linux 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6\nLinux Linux 7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6\nLinux Linux 5.0",
    "sourceHref": "",
    "cvss": {
        "score": 7.5,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
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        "baseScore": 0,
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        "attackComplexity": "",
        "privilegesRequired": "",
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        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
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            "baseScore": 0,
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            "privilegesRequired": "",
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        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Linux",
    "version": "7fb1b8ca8fa1ee34ffc328f17f78da68c7cc04e6",
    "vendor": "Linux",
    "ai_description": "",
    "ai_severity": "",
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    "ai_score": 0
}