vt: discard stale unicode buffer on alt screen exit after resize_CVE-2026-31742

{
    "lastseen": "",
    "description": "In the Linux kernel, the following vulnerability has been resolved:\n\nvt: discard stale unicode buffer on alt screen exit after resize\n\nWhen enter_alt_screen() saves vc_uni_lines into vc_saved_uni_lines and\nsets vc_uni_lines to NULL, a subsequent console resize via vc_do_resize()\nskips reallocating the unicode buffer because vc_uni_lines is NULL.\nHowever, vc_saved_uni_lines still points to the old buffer allocated for\nthe original dimensions.\n\nWhen leave_alt_screen() later restores vc_saved_uni_lines, the buffer\ndimensions no longer match vc_rows/vc_cols. Any operation that iterates\nover the unicode buffer using the current dimensions (e.g. csi_J clearing\nthe screen) will access memory out of bounds, causing a kernel oops:\n\n  BUG: unable to handle page fault for address: 0x0000002000000020\n  RIP: 0010:csi_J+0x133/0x2d0\n\nThe faulting address 0x0000002000000020 is two adjacent u32 space\ncharacters (0x20) interpreted as a pointer, read from the row data area\npast the end of the 25-entry pointer array in a buffer allocated for\n80x25 but accessed with 240x67 dimensions.\n\nFix this by checking whether the console dimensions changed while in the\nalternate screen. If they did, free the stale saved buffer instead of\nrestoring it. The unicode screen will be lazily rebuilt via\nvc_uniscr_check() when next needed.",
    "published": "2026-05-01T14:14:37.495Z",
    "modified": "2026-05-03T05:45:43.661Z",
    "type": "cve",
    "title": "vt: discard stale unicode buffer on alt screen exit after resize",
    "source": "Linux",
    "references": "https://git.kernel.org/stable/c/891d790fdb5c96c6e1d2841e06ee6c360f2d1288\nhttps://git.kernel.org/stable/c/428fdf55301e6c8fa5a36b426240797b1cf86570\nhttps://git.kernel.org/stable/c/40014493cece72a0be5672cd86763e53fb3ec613",
    "id": "CVE-2026-31742",
    "bulletinFamily": "",
    "cwe": null,
    "cvelist": null,
    "sourceData": "Linux Linux c4efef65a46f610418a3f69149c51492d31c8591\nLinux Linux 1cf66bd9127447c57295f5199029e8d8b47c6c67\nLinux Linux 5eb608319bb56464674a71b4a66ea65c6c435d64\nLinux Linux 6.18.20\nLinux Linux 6.19.10",
    "sourceHref": "",
    "cvss": {
        "score": 7.8,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
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        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
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            "privilegesRequired": "",
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            "confidentialityImpact": "",
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            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Linux",
    "version": "c4efef65a46f610418a3f69149c51492d31c8591",
    "vendor": "Linux",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
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    "ai_score": 0
}