{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2023-54269", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-12-30T12:06:44.518Z", "datePublished": "2025-12-30T12:16:00.317Z", "dateUpdated": "2026-08-05T09:18:46.870Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T09:18:46.870Z" }, "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." } ], "metrics": [ { "cvssV3_1": { "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" }, "scenarios": [ { "lang": "en", "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 — 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->users, skb->head, skb->destructor) 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->destructor and skb->head, 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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sunrpc/svc_xprt.c" ], "versions": [ { "version": "f5e13d700a4d40ccde3d36e383f9247dcb3c1d2d", "lessThan": "7851771789e87108a92697194105ef0c9307dc5e", "status": "affected", "versionType": "git" }, { "version": "773f91b2cf3f52df0d7508fdbf60f37567cdaee4", "lessThan": "fd86534872f445f54dc01e7db001e25eadf063a8", "status": "affected", "versionType": "git" }, { "version": "773f91b2cf3f52df0d7508fdbf60f37567cdaee4", "lessThan": "e0c648627322a4c7e018e5c7f837c3c03e297dbb", "status": "affected", "versionType": "git" }, { "version": "773f91b2cf3f52df0d7508fdbf60f37567cdaee4", "lessThan": "eb8d3a2c809abd73ab0a060fe971d6b9019aa3c1", "status": "affected", "versionType": "git" }, { "version": "11fab500f86403b2ebf6795feeade6e10302e448", "status": "affected", "versionType": "git" }, { "version": "5.15.35", "lessThan": "5.15.113", "status": "affected", "versionType": "semver" }, { "version": "5.17.4", "lessThan": "5.18", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sunrpc/svc_xprt.c" ], "versions": [ { "version": "5.18", "status": "affected" }, { "version": "0", "lessThan": "5.18", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.113", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.30", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.3.4", "lessThanOrEqual": "6.3.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.4", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15.35", "versionEndExcluding": "5.15.113" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "6.1.30" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "6.3.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "6.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.17.4" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/7851771789e87108a92697194105ef0c9307dc5e" }, { "url": "https://git.kernel.org/stable/c/fd86534872f445f54dc01e7db001e25eadf063a8" }, { "url": "https://git.kernel.org/stable/c/e0c648627322a4c7e018e5c7f837c3c03e297dbb" }, { "url": "https://git.kernel.org/stable/c/eb8d3a2c809abd73ab0a060fe971d6b9019aa3c1" } ], "title": "SUNRPC: double free xprt_ctxt while still in use", "x_generator": { "engine": "bippy-1.2.0" } } } }