{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64026","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-07-19T07:54:57.028Z","datePublished":"2026-07-19T15:39:17.783Z","dateUpdated":"2026-08-05T12:38:20.972Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:38:20.972Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nrxrpc: Fix DATA decrypt vs splice() by copying data to buffer in recvmsg\n\nThis improves the fix for CVE-2026-43500.\n\nFix the pagecache corruption from in-place decryption of a DATA packet\ntransmitted locally by splice() by getting rid of the packet sharing in the\nI/O thread and unconditionally extracting the packet content into a bounce\nbuffer in which the buffer is decrypted.  recvmsg() (or the kernel\nequivalent) then copies the data from the bounce buffer to the destination\nbuffer.  The sk_buff then remains unmodified.\n\nThis has an additional advantage in that the packet is then arranged in the\nbuffer with the correct alignment required for the crypto algorithms to\nprocess directly.  The performance of the crypto does seem to be a little\nfaster and, surprisingly, the unencrypted performance doesn't seem to\nchange much - possibly due to removing complexity from the I/O thread.\n\nYet another advantage is that the I/O thread doesn't have to copy packets\nwhich would slow down packet distribution, ACK generation, etc..\n\nThe buffer belongs to the call and is allocated initially at 2K,\nsufficiently large to hold a whole jumbo subpacket, but the buffer will be\nincreased in size if needed.  However, to take this work, MSG_PEEK may\ncause a later packet to be decrypted into the buffer, in which case the\nearlier one will need re-decrypting for a subsequent recvmsg().\n\nNote that rx_pkt_offset may legitimately see 0 as a valid offset now, so\nswitch to using USHRT_MAX to indicate an invalid offset.\n\nNote also that I would generally prefer to replace the buffers of the\ncurrent sk_buff with a new kmalloc'd buffer of the right size, ditching the\nold data and frags as this makes the handling of MSG_PEEK easier and\nremoves the re-decryption issue, but this looks like quite a complicated\nthing to achieve.  skb_morph() looks half way to what I want, but I don't\nwant to have to allocate a new sk_buff."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - Exploitation requires skb fragments backed by splice()-shared pagecache pages (SKBFL_SHARED_FRAG via __ip_append_data or MSG_SPLICE_PAGES on loopback TX), not packets received from a remote NIC; the corrupting decrypt runs in recvmsg()/rxrpc_kernel_recv_data() on the local receive path.\nAC:L - The attacker controls both sides of the loopback session—establishing an encrypted rxrpc call, splicing/sending DATA packets with shared frags, and calling recvmsg() to trigger in-place decryption—without depending on timing or layout they cannot influence.\nPR:L - AF_RXRPC socket creation and bind require no special capabilities; any unprivileged local user who can load/use the rxrpc module (e.g., via kafs/AFS client) can establish encrypted rxrpc sessions with session-keyring credentials.\nUI:N - Triggering pagecache corruption requires only local syscalls (socket, splice/sendmsg, recvmsg) with no victim user action such as opening files or mounting filesystems.\nS:U - The impact is in-kernel pagecache corruption on the same host; it does not cross a VM, container, or IOMMU security boundary to affect a different security authority.\nC:H - In-place decryption via skb_to_sgvec() overwrites shared pagecache pages with transformed ciphertext, constituting uncontrolled kernel memory modification that can corrupt or expose cached file data readable by other processes sharing those pages.\nI:H - The bug writes decrypted data directly into pagecache-backed pages referenced by skb frags, enabling arbitrary modification of cached file contents for any file the attacker can splice from, including world-readable shared files.\nA:H - Corrupting pagecache pages of active file mappings can cause filesystem data integrity failures, application crashes, and potential kernel panics from subsequent I/O on damaged cache state."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/rxrpc/ar-internal.h","net/rxrpc/call_event.c","net/rxrpc/call_object.c","net/rxrpc/insecure.c","net/rxrpc/recvmsg.c","net/rxrpc/rxgk.c","net/rxrpc/rxgk_common.h","net/rxrpc/rxkad.c"],"versions":[{"version":"d0d5c0cd1e711c98703f3544c1e6fc1372898de5","lessThan":"a05bf6d9e621fa71e89ccebe3047ba45218d7b38","status":"affected","versionType":"git"},{"version":"d0d5c0cd1e711c98703f3544c1e6fc1372898de5","lessThan":"b94a6ccbaf1104dd980150a65fdeb2f69d17d2f5","status":"affected","versionType":"git"},{"version":"d0d5c0cd1e711c98703f3544c1e6fc1372898de5","lessThan":"46cb765e2e5ad52303ea157e10d370bb6b7acbbf","status":"affected","versionType":"git"},{"version":"d0d5c0cd1e711c98703f3544c1e6fc1372898de5","lessThan":"c580087743712112778a06d65a4074053072d7bf","status":"affected","versionType":"git"},{"version":"d0d5c0cd1e711c98703f3544c1e6fc1372898de5","lessThan":"d2bc90cf6c75cb96d2ce549be6c35efa3099d25b","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/rxrpc/ar-internal.h","net/rxrpc/call_event.c","net/rxrpc/call_object.c","net/rxrpc/insecure.c","net/rxrpc/recvmsg.c","net/rxrpc/rxgk.c","net/rxrpc/rxgk_common.h","net/rxrpc/rxkad.c"],"versions":[{"version":"5.3","status":"affected"},{"version":"0","lessThan":"5.3","status":"unaffected","versionType":"semver"},{"version":"6.6.143","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.93","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.35","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.0.11","lessThanOrEqual":"7.0.*","status":"unaffected","versionType":"semver"},{"version":"7.1","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":"5.3","versionEndExcluding":"6.6.143"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.3","versionEndExcluding":"6.12.93"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.3","versionEndExcluding":"6.18.35"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.3","versionEndExcluding":"7.0.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.3","versionEndExcluding":"7.1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/a05bf6d9e621fa71e89ccebe3047ba45218d7b38"},{"url":"https://git.kernel.org/stable/c/b94a6ccbaf1104dd980150a65fdeb2f69d17d2f5"},{"url":"https://git.kernel.org/stable/c/46cb765e2e5ad52303ea157e10d370bb6b7acbbf"},{"url":"https://git.kernel.org/stable/c/c580087743712112778a06d65a4074053072d7bf"},{"url":"https://git.kernel.org/stable/c/d2bc90cf6c75cb96d2ce549be6c35efa3099d25b"}],"title":"rxrpc: Fix DATA decrypt vs splice() by copying data to buffer in recvmsg","x_generator":{"engine":"bippy-1.2.0"}}}}