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CVE-2023-54269 (GCVE-0-2023-54269)

Vulnerability from cvelistv5 – Published: 2025-12-30 12:16 – Updated: 2026-08-05 09:18
VLAI
Title
SUNRPC: double free xprt_ctxt while still in use
Summary
In the Linux kernel, the following vulnerability has been resolved: SUNRPC: double free xprt_ctxt while still in use When an RPC request is deferred, the rq_xprt_ctxt pointer is moved out of the svc_rqst into the svc_deferred_req. When the deferred request is revisited, the pointer is copied into the new svc_rqst - and also remains in the svc_deferred_req. In the (rare?) case that the request is deferred a second time, the old svc_deferred_req is reused - it still has all the correct content. However in that case the rq_xprt_ctxt pointer is NOT cleared so that when xpo_release_xprt is called, the ctxt is freed (UDP) or possible added to a free list (RDMA). When the deferred request is revisited for a second time, it will reference this ctxt which may be invalid, and the free the object a second time which is likely to oops. So change svc_defer() to *always* clear rq_xprt_ctxt, and assert that the value is now stored in the svc_deferred_req.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: f5e13d700a4d40ccde3d36e383f9247dcb3c1d2d , < 7851771789e87108a92697194105ef0c9307dc5e (git)
Affected: 773f91b2cf3f52df0d7508fdbf60f37567cdaee4 , < fd86534872f445f54dc01e7db001e25eadf063a8 (git)
Affected: 773f91b2cf3f52df0d7508fdbf60f37567cdaee4 , < e0c648627322a4c7e018e5c7f837c3c03e297dbb (git)
Affected: 773f91b2cf3f52df0d7508fdbf60f37567cdaee4 , < eb8d3a2c809abd73ab0a060fe971d6b9019aa3c1 (git)
Affected: 11fab500f86403b2ebf6795feeade6e10302e448 (git)
Affected: 5.15.35 , < 5.15.113 (semver)
Affected: 5.17.4 , < 5.18 (semver)
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Linux Linux Affected: 5.18
Unaffected: 0 , < 5.18 (semver)
Unaffected: 5.15.113 , ≤ 5.15.* (semver)
Unaffected: 6.1.30 , ≤ 6.1.* (semver)
Unaffected: 6.3.4 , ≤ 6.3.* (semver)
Unaffected: 6.4 , ≤ * (original_commit_for_fix)
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              "status": "unaffected",
              "version": "6.3.4",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "6.4",
              "versionType": "original_commit_for_fix"
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      "cpeApplicability": [
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                  "versionStartIncluding": "5.15.35",
                  "vulnerable": true
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              "negate": false,
              "operator": "OR"
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      "descriptions": [
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: double free xprt_ctxt while still in use\n\nWhen an RPC request is deferred, the rq_xprt_ctxt pointer is moved out\nof the svc_rqst into the svc_deferred_req.\nWhen the deferred request is revisited, the pointer is copied into\nthe new svc_rqst - and also remains in the svc_deferred_req.\n\nIn the (rare?) case that the request is deferred a second time, the old\nsvc_deferred_req is reused - it still has all the correct content.\nHowever in that case the rq_xprt_ctxt pointer is NOT cleared so that\nwhen xpo_release_xprt is called, the ctxt is freed (UDP) or possible\nadded to a free list (RDMA).\nWhen the deferred request is revisited for a second time, it will\nreference this ctxt which may be invalid, and the free the object a\nsecond time which is likely to oops.\n\nSo change svc_defer() to *always* clear rq_xprt_ctxt, and assert that\nthe value is now stored in the svc_deferred_req."
        }
      ],
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            "baseSeverity": "CRITICAL",
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            "version": "3.1"
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              "value": "AV:N - The vulnerable path is nfsd/sunrpc server-side request processing driven entirely by RPC datagrams received from remote clients over UDP port 2049 (or NFS/RDMA). No local access is needed; the attacker only sends network packets to the NFS server.\nAC:L - The attacker controls both deferral triggers \u2014 a novel (freely spoofable) UDP source address forces an ip_map cache miss, and an unresolved export/filehandle forces a second nfsd_fh/nfsd_export miss on the same request, which is exactly the first-contact sequence for a new client. Small datagrams stay linear so rq_xprt_ctxt is populated, making the trigger repeatable at will.\nPR:N - The deferrals occur inside svcauth_unix_set_client() and the export lookup, i.e. while the server is still deciding whether the client is permitted at all, so no credentials have been verified. AUTH_NULL/AUTH_UNIX requests from any host able to reach the nfsd port suffice.\nUI:N - nfsd threads process incoming RPCs and requeue deferred requests automatically with no action by any local user or administrator.\nS:U - The corruption is confined to kernel memory managed by the same kernel security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The freed sk_buff is re-read and re-released (skb-\u003eusers, skb-\u003ehead, skb-\u003edestructor) and the double free returns the same slab object to two owners, giving type-confusion-based read primitives over adjacent kernel data. Per UAF guidance this is High.\nI:H - A double free of an sk_buff lets a remote attacker who reallocates the slot with sprayed packet data control fields such as skb-\u003edestructor and skb-\u003ehead, yielding arbitrary write / control-flow hijack; the RDMA variant double-adds a recv ctxt to the free list so two live receives share one DMA buffer.\nA:H - The commit itself notes the second free \"is likely to oops\"; a double free of an sk_buff or corruption of the RDMA recv ctxt free list panics the kernel and can be re-triggered repeatedly by an unauthenticated remote client."
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        "dateUpdated": "2026-08-05T09:18:46.870Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/7851771789e87108a92697194105ef0c9307dc5e"
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    "assignerShortName": "Linux",
    "cveId": "CVE-2023-54269",
    "datePublished": "2025-12-30T12:16:00.317Z",
    "dateReserved": "2025-12-30T12:06:44.518Z",
    "dateUpdated": "2026-08-05T09:18:46.870Z",
    "state": "PUBLISHED"
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      "date": "2026-09-16",
      "epss": "0.00531",
      "percentile": "0.43573"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2023-54269\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-12-30T13:16:15.737\",\"lastModified\":\"2026-08-04T11:16:38.893\",\"vulnStatus\":\"Deferred\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nSUNRPC: double free xprt_ctxt while still in use\\n\\nWhen an RPC request is deferred, the rq_xprt_ctxt pointer is moved out\\nof the svc_rqst into the svc_deferred_req.\\nWhen the deferred request is revisited, the pointer is copied into\\nthe new svc_rqst - and also remains in the svc_deferred_req.\\n\\nIn the (rare?) case that the request is deferred a second time, the old\\nsvc_deferred_req is reused - it still has all the correct content.\\nHowever in that case the rq_xprt_ctxt pointer is NOT cleared so that\\nwhen xpo_release_xprt is called, the ctxt is freed (UDP) or possible\\nadded to a free list (RDMA).\\nWhen the deferred request is revisited for a second time, it will\\nreference this ctxt which may be invalid, and the free the object a\\nsecond time which is likely to oops.\\n\\nSo change svc_defer() to *always* clear rq_xprt_ctxt, and assert that\\nthe value is now stored in the svc_deferred_req.\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\\n\\nSUNRPC: doble liberaci\u00f3n de xprt_ctxt mientras a\u00fan est\u00e1 en uso\\n\\nCuando una solicitud RPC es diferida, el puntero rq_xprt_ctxt es movido fuera del svc_rqst hacia el svc_deferred_req.\\nCuando la solicitud diferida es revisitada, el puntero es copiado en el nuevo svc_rqst - y tambi\u00e9n permanece en el svc_deferred_req.\\n\\nEn el caso (\u00bfraro?) de que la solicitud sea diferida por segunda vez, el antiguo svc_deferred_req es reutilizado - a\u00fan tiene todo el contenido correcto.\\nSin embargo, en ese caso el puntero rq_xprt_ctxt NO es limpiado de modo que cuando se llama a xpo_release_xprt, el ctxt es liberado (UDP) o posiblemente a\u00f1adido a una lista de libres (RDMA).\\nCuando la solicitud diferida es revisitada por segunda vez, har\u00e1 referencia a este ctxt el cual puede ser inv\u00e1lido, y liberar\u00e1 el objeto por segunda vez lo que probablemente causar\u00e1 un \u0027oops\u0027.\\n\\nAs\u00ed que cambie svc_defer() para *siempre* limpiar rq_xprt_ctxt, y afirme que el valor ahora est\u00e1 almacenado en el svc_deferred_req.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"net/sunrpc/svc_xprt.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"f5e13d700a4d40ccde3d36e383f9247dcb3c1d2d\",\"lessThan\":\"7851771789e87108a92697194105ef0c9307dc5e\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"773f91b2cf3f52df0d7508fdbf60f37567cdaee4\",\"lessThan\":\"fd86534872f445f54dc01e7db001e25eadf063a8\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"773f91b2cf3f52df0d7508fdbf60f37567cdaee4\",\"lessThan\":\"e0c648627322a4c7e018e5c7f837c3c03e297dbb\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"773f91b2cf3f52df0d7508fdbf60f37567cdaee4\",\"lessThan\":\"eb8d3a2c809abd73ab0a060fe971d6b9019aa3c1\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"11fab500f86403b2ebf6795feeade6e10302e448\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"5.15.35\",\"lessThan\":\"5.15.113\",\"versionType\":\"semver\",\"status\":\"affected\"},{\"version\":\"5.17.4\",\"lessThan\":\"5.18\",\"versionType\":\"semver\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"net/sunrpc/svc_xprt.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"5.18\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"5.18\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.15.113\",\"lessThanOrEqual\":\"5.15.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.30\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.3.4\",\"lessThanOrEqual\":\"6.3.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.4\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":9.8,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/7851771789e87108a92697194105ef0c9307dc5e\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/e0c648627322a4c7e018e5c7f837c3c03e297dbb\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/eb8d3a2c809abd73ab0a060fe971d6b9019aa3c1\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/fd86534872f445f54dc01e7db001e25eadf063a8\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-04T19:13:28+00:00",
      "cve": "CVE-2023-54269",
      "id": "CVE-2023-54269",
      "initial_release_date": "2023-01-01T00:00:00+00:00",
      "product_status:fixed": "128",
      "product_status:known_affected": "138",
      "product_status:known_not_affected": "104",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: SUNRPC: double free xprt_ctxt while still in use",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2023/cve-2023-54269.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-05T23:39:15Z",
      "cve": "CVE-2023-54269",
      "id": "CVE-2023-54269",
      "initial_release_date": "2025-12-31T00:27:04Z",
      "product_status:known_affected": "354",
      "product_status:known_not_affected": "432",
      "product_status:recommended": "245",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2023-54269",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2023-54269.json",
      "version": "24"
    }
  }
}



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