{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2024-42108","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2024-07-29T15:50:41.176Z","datePublished":"2024-07-30T07:46:03.517Z","dateUpdated":"2026-08-05T11:35:40.063Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T11:35:40.063Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: rswitch: Avoid use-after-free in rswitch_poll()\n\nThe use-after-free is actually in rswitch_tx_free(), which is inlined in\nrswitch_poll(). Since `skb` and `gq->skbs[gq->dirty]` are in fact the\nsame pointer, the skb is first freed using dev_kfree_skb_any(), then the\nvalue in skb->len is used to update the interface statistics.\n\nLet's move around the instructions to use skb->len before the skb is\nfreed.\n\nThis bug is trivial to reproduce using KFENCE. It will trigger a splat\nevery few packets. A simple ARP request or ICMP echo request is enough."}],"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 UAF fires on every hardware TX completion, and an unauthenticated remote host reaches it simply by sending any packet that elicits a reply (ICMP echo request, TCP SYN to a closed port, any service response) — all routable across L3, not just link-local. The fix commit itself states an ARP or ICMP echo request is sufficient to trigger it.\nAC:L - There is no race, no timing window, and no memory-layout precondition — `skb->len` is read unconditionally one statement after `dev_kfree_skb_any()` on every TX-completed skb, and the attacker sets the pace by sending packets. The commit reports a splat \"every few packets,\" so even the KFENCE-guarded-slot case is hit trivially by a sustained flood.\nPR:N - The reply packet is generated by the kernel network stack before any application-layer authentication, so no credentials, session, or account on the target are needed. Recovering the leaked word afterwards requires only a world-readable counter in `/proc/net/dev`.\nUI:N - The attacker sends the packets themselves and the TX-completion NAPI poll runs autonomously; no victim login, mount, file open, or any other action is involved.\nS:U - The use-after-free read, the leaked freelist word, and the resulting fault all stay inside the kernel's own memory and the rswitch driver's security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - Because `skbuff_head_cache` has no ctor/RCU/poison flags, SLUB places the freelist pointer at ~offset 112 — precisely where `skb->len` sits — so the freed-memory read pulls the low 32 bits of a kernel heap pointer and adds it into `stats.tx_bytes`, which `rswitch_get_stats()` exports verbatim to `/proc/net/dev` and sysfs. Differencing the counter around a single TX completion recovers that word exactly and repeatably, giving a reliable kernel heap-address/KASLR disclosure; per kernel scoring guidance a use-after-free is High regardless.\nI:H - This is a use-after-free on an object in the general-purpose `skbuff_head_cache`, which per kernel scoring guidance is rated High since freed-object accesses in that cache are the standard primitive for heap grooming and control-flow corruption. Concretely, kernel-maintained interface accounting is corrupted with freed slab contents, poisoning the statistics that monitoring and traffic-accounting decisions rely on.\nA:H - On the many kernels shipping `CONFIG_KFENCE=y` (Android GKI, Fedora, RHEL, Ubuntu, hardened automotive builds) the freed object's page is unmapped, so the `skb->len` read page-faults into `kfence_report_error()`, which calls `check_panic_on_warn(\"KFENCE\")` — an immediate kernel panic on the fail-fast configurations typical for an in-vehicle R-Car S4 gateway. A remote attacker can drive this indefinitely with a ping flood, and any use-after-free is rated High for availability."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ethernet/renesas/rswitch.c"],"versions":[{"version":"0aeec4bb6a9fc963932bf3c929bdf27d835d44e9","lessThan":"4a41bb9f2b402469d425a1c13359d3b3ea4e6403","status":"affected","versionType":"git"},{"version":"271e015b91535dd87fd0f5df0cc3b906c2eddef9","lessThan":"92cbbe7759193e3418f38d0d73f8fe125312c58b","status":"affected","versionType":"git"},{"version":"271e015b91535dd87fd0f5df0cc3b906c2eddef9","lessThan":"9a0c28efeec6383ef22e97437616b920e7320b67","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ethernet/renesas/rswitch.c"],"versions":[{"version":"6.8","status":"affected"},{"version":"0","lessThan":"6.8","status":"unaffected","versionType":"semver"},{"version":"6.9.9","lessThanOrEqual":"6.9.*","status":"unaffected","versionType":"semver"},{"version":"6.10","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":"6.8","versionEndExcluding":"6.9.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"6.10"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/4a41bb9f2b402469d425a1c13359d3b3ea4e6403"},{"url":"https://git.kernel.org/stable/c/92cbbe7759193e3418f38d0d73f8fe125312c58b"},{"url":"https://git.kernel.org/stable/c/9a0c28efeec6383ef22e97437616b920e7320b67"}],"title":"net: rswitch: Avoid use-after-free in rswitch_poll()","x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2024-08-02T04:54:32.138Z"},"title":"CVE Program Container","references":[{"url":"https://git.kernel.org/stable/c/92cbbe7759193e3418f38d0d73f8fe125312c58b","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/9a0c28efeec6383ef22e97437616b920e7320b67","tags":["x_transferred"]}]},{"metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2024-42108","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2024-09-10T16:17:39.409257Z"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2024-09-11T17:33:07.014Z"}}]}}