{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-68775", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-12-24T10:30:51.035Z", "datePublished": "2026-01-13T15:28:52.069Z", "dateUpdated": "2026-08-05T12:11:25.376Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:11:25.376Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/handshake: duplicate handshake cancellations leak socket\n\nWhen a handshake request is cancelled it is removed from the\nhandshake_net->hn_requests list, but it is still present in the\nhandshake_rhashtbl until it is destroyed.\n\nIf a second cancellation request arrives for the same handshake request,\nthen remove_pending() will return false... and assuming\nHANDSHAKE_F_REQ_COMPLETED isn't set in req->hr_flags, we'll continue\nprocessing through the out_true label, where we put another reference on\nthe sock and a refcount underflow occurs.\n\nThis can happen for example if a handshake times out - particularly if\nthe SUNRPC client sends the AUTH_TLS probe to the server but doesn't\nfollow it up with the ClientHello due to a problem with tlshd. When the\ntimeout is hit on the server, the server will send a FIN, which triggers\na cancellation request via xs_reset_transport(). When the timeout is\nhit on the client, another cancellation request happens via\nxs_tls_handshake_sync().\n\nAdd a test_and_set_bit(HANDSHAKE_F_REQ_COMPLETED) in the pending cancel\npath so duplicate cancels can be detected." } ], "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 - An unauthenticated remote client can reach the bug through a network-facing SUNRPC/NFS server by sending an AUTH_TLS NULL probe. TCP receive processing reaches svcauth_tls_accept(), svc_tcp_handshake(), and ultimately duplicate handshake cancellation.\nAC:L - The attacker can create and abandon concurrent AUTH_TLS connections to keep requests pending and drive both timeout and transport-teardown cancellations. No memory-layout guess or uncontrollable race is required.\nPR:N - AUTH_TLS is processed before RPC credentials are authenticated, and the probe requires no established identity, account, or kernel capability.\nUI:N - The server processes the probe, timeout, and socket teardown automatically without victim user action.\nS:U - Exploitation affects the same host-kernel security authority processing the request and does not cross a VM, IOMMU, or comparable security boundary.\nC:H - The extra sock_put() can prematurely free a still-referenced socket, producing a reclaimable kernel use-after-free capable of exposing arbitrary kernel memory.\nI:H - Reclaiming the prematurely freed socket object can provide attacker-controlled data to subsequent kernel accesses, enabling arbitrary modification or control-flow hijacking.\nA:H - The socket use-after-free can cause a kernel oops or panic, while repeated unauthenticated triggers can also leak sockets and exhaust resources." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/handshake/request.c" ], "versions": [ { "version": "3b3009ea8abb713b022d94fba95ec270cf6e7eae", "lessThan": "011ae80c49d9bfa5b4336f8bd387cd25c7593663", "status": "affected", "versionType": "git" }, { "version": "3b3009ea8abb713b022d94fba95ec270cf6e7eae", "lessThan": "e1641177e7fb48a0a5a06658d4aab51da6656659", "status": "affected", "versionType": "git" }, { "version": "3b3009ea8abb713b022d94fba95ec270cf6e7eae", "lessThan": "3c330f1dee3cd92b57e19b9d21dc8ce5970b09be", "status": "affected", "versionType": "git" }, { "version": "3b3009ea8abb713b022d94fba95ec270cf6e7eae", "lessThan": "15564bd67e2975002f2a8e9defee33e321d3183f", "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/handshake/request.c" ], "versions": [ { "version": "6.4", "status": "affected" }, { "version": "0", "lessThan": "6.4", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.120", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.64", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.3", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19", "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": "6.4", "versionEndExcluding": "6.6.120" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.4", "versionEndExcluding": "6.12.64" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.4", "versionEndExcluding": "6.18.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.4", "versionEndExcluding": "6.19" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/011ae80c49d9bfa5b4336f8bd387cd25c7593663" }, { "url": "https://git.kernel.org/stable/c/e1641177e7fb48a0a5a06658d4aab51da6656659" }, { "url": "https://git.kernel.org/stable/c/3c330f1dee3cd92b57e19b9d21dc8ce5970b09be" }, { "url": "https://git.kernel.org/stable/c/15564bd67e2975002f2a8e9defee33e321d3183f" } ], "title": "net/handshake: duplicate handshake cancellations leak socket", "x_generator": { "engine": "bippy-1.2.0" } } } }