clsact: Fix use-after-free in init/destroy rollback asymmetry_CVE-2026-23413

{
    "lastseen": "",
    "description": "In the Linux kernel, the following vulnerability has been resolved:\n\nclsact: Fix use-after-free in init/destroy rollback asymmetry\n\nFix a use-after-free in the clsact qdisc upon init/destroy rollback asymmetry.\nThe latter is achieved by first fully initializing a clsact instance, and\nthen in a second step having a replacement failure for the new clsact qdisc\ninstance. clsact_init() initializes ingress first and then takes care of the\negress part. This can fail midway, for example, via tcf_block_get_ext(). Upon\nfailure, the kernel will trigger the clsact_destroy() callback.\n\nCommit 1cb6f0bae504 (\"bpf: Fix too early release of tcx_entry\") details the\nway how the transition is happening. If tcf_block_get_ext on the q->ingress_block\nends up failing, we took the tcx_miniq_inc reference count on the ingress\nside, but not yet on the egress side. clsact_destroy() tests whether the\n{ingress,egress}_entry was non-NULL. However, even in midway failure on the\nreplacement, both are in fact non-NULL with a valid egress_entry from the\nprevious clsact instance.\n\nWhat we really need to test for is whether the qdisc instance-specific ingress\nor egress side previously got initialized. This adds a small helper for checking\nthe miniq initialization called mini_qdisc_pair_inited, and utilizes that upon\nclsact_destroy() in order to fix the use-after-free scenario. Convert the\ningress_destroy() side as well so both are consistent to each other.",
    "published": "2026-04-02T11:40:54.384Z",
    "modified": "2026-04-27T14:02:12.056Z",
    "type": "cve",
    "title": "clsact: Fix use-after-free in init/destroy rollback asymmetry",
    "source": "Linux",
    "references": "https://git.kernel.org/stable/c/a73d95b57bf9faebdfed591bcb7ed9292062a84c\nhttps://git.kernel.org/stable/c/37bef86e5428d59f70a4da82b80f9a8f252fecbe\nhttps://git.kernel.org/stable/c/4c9af67f99aa3e51b522c54968ab3ac8272be41c\nhttps://git.kernel.org/stable/c/0509b762bc5e8ea7b8391130730c6d8502fc6e69\nhttps://git.kernel.org/stable/c/a0671125d4f55e1e98d9bde8a0b671941987e208",
    "id": "CVE-2026-23413",
    "bulletinFamily": "",
    "cwe": null,
    "cvelist": null,
    "sourceData": "Linux Linux 230bb13650b0f186f540500fd5f5f7096a822a2a\nLinux Linux 1cb6f0bae50441f4b4b32a28315853b279c7404e\nLinux Linux 1cb6f0bae50441f4b4b32a28315853b279c7404e\nLinux Linux 1cb6f0bae50441f4b4b32a28315853b279c7404e\nLinux Linux 1cb6f0bae50441f4b4b32a28315853b279c7404e\nLinux Linux f61ecf1bd5b562ebfd7d430ccb31619857e80857\nLinux Linux 6.10",
    "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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        "baseScore": 0,
        "baseSeverity": "",
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        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
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            "baseScore": 0,
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            "privilegesRequired": "",
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        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Linux",
    "version": "230bb13650b0f186f540500fd5f5f7096a822a2a",
    "vendor": "Linux",
    "ai_description": "",
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    "ai_score": 0
}