{"id":"CVE-2026-74545","state":"PUBLISHED","title":"rtase: fix double free of multi-frag skb on DMA map failure","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nrtase: fix double free of multi-frag skb on DMA map failure\n\nIn rtase_start_xmit(), when the head buffer DMA mapping fails after\nrtase_xmit_frags() has mapped all fragments, the error path clears\nthe fragment descriptors with rtase_tx_clear_range(), which frees\nthe skb through the last-frag slot and accounts tx_dropped. Control\nthen falls through to the common error label, which frees the same\nskb a second time and counts it again.\n\nReturn right after clearing the fragments when the skb owns frags;\nthe no-frag case still drops through and frees the head skb once.","publishedAt":"2026-08-15T12:27:54.536Z","updatedAt":"2026-08-17T05:48:32.121Z","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":"d6e882b89fdf80be0ab4f914ec10f75215e49495","status":"affected","lessThan":"4f09172aff5f73a5e914f4fbc0d00a1c2ea9f7cb","versionType":"git"},{"version":"d6e882b89fdf80be0ab4f914ec10f75215e49495","status":"affected","lessThan":"db986098f30881fafcc752800aa3b13fd289c922","versionType":"git"},{"version":"d6e882b89fdf80be0ab4f914ec10f75215e49495","status":"affected","lessThan":"de691dc3227b061c4d0beba9f0128fe1ff33dd68","versionType":"git"},{"version":"d6e882b89fdf80be0ab4f914ec10f75215e49495","status":"affected","lessThan":"6fb7b769d6ed6d1d2e02af4a80e57a2477f35086","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ethernet/realtek/rtase/rtase_main.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.12","versionType":"semver"},{"version":"6.12.103","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.44","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.8","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ethernet/realtek/rtase/rtase_main.c"]}],"references":["https://git.kernel.org/stable/c/4f09172aff5f73a5e914f4fbc0d00a1c2ea9f7cb","https://git.kernel.org/stable/c/db986098f30881fafcc752800aa3b13fd289c922","https://git.kernel.org/stable/c/de691dc3227b061c4d0beba9f0128fe1ff33dd68","https://git.kernel.org/stable/c/6fb7b769d6ed6d1d2e02af4a80e57a2477f35086"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/74xxx/CVE-2026-74545.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-74545","state":"PUBLISHED","datePublished":"2026-08-15T12:27:54.536Z","dateUpdated":"2026-08-17T05:48:32.121Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-15T05:44:03.914Z"},"containers":{"cna":{"title":"rtase: fix double free of multi-frag skb on DMA map failure","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nrtase: fix double free of multi-frag skb on DMA map failure\n\nIn rtase_start_xmit(), when the head buffer DMA mapping fails after\nrtase_xmit_frags() has mapped all fragments, the error path clears\nthe fragment descriptors with rtase_tx_clear_range(), which frees\nthe skb through the last-frag slot and accounts tx_dropped. Control\nthen falls through to the common error label, which frees the same\nskb a second time and counts it again.\n\nReturn right after clearing the fragments when the skb owns frags;\nthe no-frag case still drops through and frees the head skb once."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d6e882b89fdf80be0ab4f914ec10f75215e49495","status":"affected","lessThan":"4f09172aff5f73a5e914f4fbc0d00a1c2ea9f7cb","versionType":"git"},{"version":"d6e882b89fdf80be0ab4f914ec10f75215e49495","status":"affected","lessThan":"db986098f30881fafcc752800aa3b13fd289c922","versionType":"git"},{"version":"d6e882b89fdf80be0ab4f914ec10f75215e49495","status":"affected","lessThan":"de691dc3227b061c4d0beba9f0128fe1ff33dd68","versionType":"git"},{"version":"d6e882b89fdf80be0ab4f914ec10f75215e49495","status":"affected","lessThan":"6fb7b769d6ed6d1d2e02af4a80e57a2477f35086","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ethernet/realtek/rtase/rtase_main.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.12","versionType":"semver"},{"version":"6.12.103","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.44","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.8","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/ethernet/realtek/rtase/rtase_main.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/4f09172aff5f73a5e914f4fbc0d00a1c2ea9f7cb"},{"url":"https://git.kernel.org/stable/c/db986098f30881fafcc752800aa3b13fd289c922"},{"url":"https://git.kernel.org/stable/c/de691dc3227b061c4d0beba9f0128fe1ff33dd68"},{"url":"https://git.kernel.org/stable/c/6fb7b769d6ed6d1d2e02af4a80e57a2477f35086"}],"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 flaw is in rtase_start_xmit (ndo_start_xmit) on the Realtek Automotive Switch PCIe netdev; a remote peer can reach it by sending traffic that the host forwards, bridges, or answers out the rtase interface on automotive gateways and industrial routers without local shell access.\nAC:L - NETIF_F_SG enables multi-fragment TX skbs that rtase_xmit_frags maps before the head; an attacker can reliably create such packets and pressure SWIOTLB/IOVA resources with concurrent egress so the final head dma_map_single fails after fragment mapping succeeds, deterministically hitting the buggy error path.\nPR:N - Exploitation needs only the ability to inject or induce network traffic transmitted via the rtase netdev; no target credentials, capabilities, or local account are required on forwarding automotive/industrial gateways where this driver is deployed.\nUI:N - No victim interaction is required; the double free occurs automatically when the kernel queues a multi-fragment skb and the head DMA mapping fails during normal transmit error handling.\nS:U - The double free corrupts kernel heap allocator state on the host running the rtase driver; it does not cross VM, container, or IOMMU security boundaries.\nC:H - Double-freeing the same skb is kernel heap memory corruption that can corrupt freelist metadata and enable reuse of freed skb memory for arbitrary kernel memory disclosure, not merely a bounded leak.\nI:H - Heap corruption from freeing the same skb twice can be shaped into arbitrary kernel memory writes or control-flow hijacking via slab reuse, not limited to dropping a single packet.\nA:H - Double-freeing an skb reliably corrupts the slab allocator and can trigger immediate oops, panic, or watchdog reset; the attacker can repeat multi-fragment transmits under DMA pressure for sustained denial of service on safety-critical automotive networks."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T05:48:32.121Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"6.12.103"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"6.18.44"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"7.1.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}