{"id":"CVE-2023-54269","state":"PUBLISHED","title":"SUNRPC: double free xprt_ctxt while still in use","description":"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.","publishedAt":"2025-12-30T12:16:00.317Z","updatedAt":"2026-10-15T21:41:43.730Z","severity":{"score":9.8,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"f5e13d700a4d40ccde3d36e383f9247dcb3c1d2d","status":"affected","lessThan":"7851771789e87108a92697194105ef0c9307dc5e","versionType":"git"},{"version":"773f91b2cf3f52df0d7508fdbf60f37567cdaee4","status":"affected","lessThan":"fd86534872f445f54dc01e7db001e25eadf063a8","versionType":"git"},{"version":"773f91b2cf3f52df0d7508fdbf60f37567cdaee4","status":"affected","lessThan":"e0c648627322a4c7e018e5c7f837c3c03e297dbb","versionType":"git"},{"version":"773f91b2cf3f52df0d7508fdbf60f37567cdaee4","status":"affected","lessThan":"eb8d3a2c809abd73ab0a060fe971d6b9019aa3c1","versionType":"git"},{"version":"11fab500f86403b2ebf6795feeade6e10302e448","status":"affected","versionType":"git"},{"version":"5.15.35","status":"affected","lessThan":"5.15.113","versionType":"semver"},{"version":"5.17.4","status":"affected","lessThan":"5.18","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sunrpc/svc_xprt.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.18","versionType":"semver"},{"version":"5.15.113","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.30","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.3.4","status":"unaffected","lessThanOrEqual":"6.3.*","versionType":"semver"},{"version":"6.4","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sunrpc/svc_xprt.c"]}],"references":["https://git.kernel.org/stable/c/7851771789e87108a92697194105ef0c9307dc5e","https://git.kernel.org/stable/c/fd86534872f445f54dc01e7db001e25eadf063a8","https://git.kernel.org/stable/c/e0c648627322a4c7e018e5c7f837c3c03e297dbb","https://git.kernel.org/stable/c/eb8d3a2c809abd73ab0a060fe971d6b9019aa3c1"],"weaknesses":[],"ingestedAt":"2026-10-29T20:06:42.242Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2023/54xxx/CVE-2023-54269.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2023-54269","state":"PUBLISHED","datePublished":"2025-12-30T12:16:00.317Z","dateUpdated":"2026-10-15T21:41:43.730Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-12-30T12:06:44.518Z"},"containers":{"cna":{"title":"SUNRPC: double free xprt_ctxt while still in use","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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"f5e13d700a4d40ccde3d36e383f9247dcb3c1d2d","status":"affected","lessThan":"7851771789e87108a92697194105ef0c9307dc5e","versionType":"git"},{"version":"773f91b2cf3f52df0d7508fdbf60f37567cdaee4","status":"affected","lessThan":"fd86534872f445f54dc01e7db001e25eadf063a8","versionType":"git"},{"version":"773f91b2cf3f52df0d7508fdbf60f37567cdaee4","status":"affected","lessThan":"e0c648627322a4c7e018e5c7f837c3c03e297dbb","versionType":"git"},{"version":"773f91b2cf3f52df0d7508fdbf60f37567cdaee4","status":"affected","lessThan":"eb8d3a2c809abd73ab0a060fe971d6b9019aa3c1","versionType":"git"},{"version":"11fab500f86403b2ebf6795feeade6e10302e448","status":"affected","versionType":"git"},{"version":"5.15.35","status":"affected","lessThan":"5.15.113","versionType":"semver"},{"version":"5.17.4","status":"affected","lessThan":"5.18","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sunrpc/svc_xprt.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.18","versionType":"semver"},{"version":"5.15.113","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.30","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.3.4","status":"unaffected","lessThanOrEqual":"6.3.*","versionType":"semver"},{"version":"6.4","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/sunrpc/svc_xprt.c"]}],"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"}],"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."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T09:18:46.870Z"},"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"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2023-54269","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-15T21:39:56.402453Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-15T21:41:43.730Z"}}]}}}