{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-38571", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T04:51:24.025Z", "datePublished": "2025-08-19T17:02:51.620Z", "dateUpdated": "2026-08-05T12:02:59.633Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:02:59.633Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsunrpc: fix client side handling of tls alerts\n\nA security exploit was discovered in NFS over TLS in tls_alert_recv\ndue to its assumption that there is valid data in the msghdr's\niterator's kvec.\n\nInstead, this patch proposes the rework how control messages are\nsetup and used by sock_recvmsg().\n\nIf no control message structure is setup, kTLS layer will read and\nprocess TLS data record types. As soon as it encounters a TLS control\nmessage, it would return an error. At that point, NFS can setup a kvec\nbacked control buffer and read in the control message such as a TLS\nalert. Scott found that a msg iterator can advance the kvec pointer\nas a part of the copy process thus we need to revert the iterator\nbefore calling into the tls_alert_recv." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H", "baseScore": 8.2, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - The vulnerable code is the SUNRPC/NFS client's TCP-with-TLS receive path, driven entirely by records arriving from the remote RPC peer over the network. A malicious NFS server — or, with `xprtsec=tls` (anonymous TLS, `tls_client_hello_anon`), any on-path attacker impersonating it — triggers the bug purely by sending crafted RPC framing followed by a TLS alert record.\nAC:L - The attacker controls both halves of the trigger: an RPC fragment with a bogus calldir or unmatched XID forces the client into the `ITER_DISCARD` path, and an ordinary TLS alert record (even a close_notify) is then sent at will, yielding a deterministic NULL dereference with no race, no memory-layout guessing, and no reliance on victim state.\nPR:N - No credentials or privileges on the victim client are needed; the attacker acts as the TLS peer. With `xprtsec=tls` the peer is entirely unauthenticated (RFC 9289 opportunistic TLS), so even an unauthenticated MITM qualifies, and alerts are processed regardless of RPC-level authentication.\nUI:N - Exploitation needs no action from any user or administrator at attack time — the NFS-over-TLS mount is pre-existing, and the bug fires from the `xprtiod` workqueue receive path as soon as the attacker's records arrive.\nS:U - The faulting code, the corrupted read, and the resulting crash are all inside the kernel's own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:L - On the bvec and past-the-end-kvec paths `tls_alert_recv()` reads two bytes through a type-confused or out-of-bounds pointer (a `struct page *` mistaken for `iov_base`, or an adjacent stack/heap word), leaking kernel memory into the `tls_alert_recv` tracepoint and into a fatal/non-fatal error oracle. The disclosure is real but strictly bounded to two bytes and is not returned to the attacker in bulk.\nI:N - `tls_alert_recv()` only reads through the bad pointer — there is no out-of-bounds write, no use-after-free, and no type confusion that yields a write primitive. The only effect is a bogus alert level selecting `-EACCES` versus `-EAGAIN` in the client's error handling.\nA:H - The `ITER_DISCARD` path dereferences a NULL kvec (and the exhausted-kvec path dereferences a garbage pointer read past the array), producing a kernel oops in the `xprtiod` kworker that kills the RPC receive worker and wedges all NFS I/O on that transport, or panics the machine outright where `panic_on_oops` is set." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sunrpc/xprtsock.c" ], "versions": [ { "version": "dea034b963c8901bdcc3d3880c04f0d75c95112f", "lessThan": "a55b3d15331859d9fdd261cfa6d34ca2aeb0fb95", "status": "affected", "versionType": "git" }, { "version": "dea034b963c8901bdcc3d3880c04f0d75c95112f", "lessThan": "c36b2fbd60e8f9c6f975522130998608880c93be", "status": "affected", "versionType": "git" }, { "version": "dea034b963c8901bdcc3d3880c04f0d75c95112f", "lessThan": "3ee397eaaca4fa04db21bb98c8f1d0c6cc525368", "status": "affected", "versionType": "git" }, { "version": "dea034b963c8901bdcc3d3880c04f0d75c95112f", "lessThan": "3feada5baf4dc96e151ff2ca54630e1d274e5458", "status": "affected", "versionType": "git" }, { "version": "dea034b963c8901bdcc3d3880c04f0d75c95112f", "lessThan": "cc5d59081fa26506d02de2127ab822f40d88bc5a", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/sunrpc/xprtsock.c" ], "versions": [ { "version": "6.5", "status": "affected" }, { "version": "0", "lessThan": "6.5", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.102", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.42", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.15.10", "lessThanOrEqual": "6.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.16.1", "lessThanOrEqual": "6.16.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.17", "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": "6.5", "versionEndExcluding": "6.6.102" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.5", "versionEndExcluding": "6.12.42" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.5", "versionEndExcluding": "6.15.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.5", "versionEndExcluding": "6.16.1" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.5", "versionEndExcluding": "6.17" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/a55b3d15331859d9fdd261cfa6d34ca2aeb0fb95" }, { "url": "https://git.kernel.org/stable/c/c36b2fbd60e8f9c6f975522130998608880c93be" }, { "url": "https://git.kernel.org/stable/c/3ee397eaaca4fa04db21bb98c8f1d0c6cc525368" }, { "url": "https://git.kernel.org/stable/c/3feada5baf4dc96e151ff2ca54630e1d274e5458" }, { "url": "https://git.kernel.org/stable/c/cc5d59081fa26506d02de2127ab822f40d88bc5a" } ], "title": "sunrpc: fix client side handling of tls alerts", "x_generator": { "engine": "bippy-1.2.0" } } } }