{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-72393", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-09T03:40:39.924Z", "datePublished": "2026-08-15T05:56:21.081Z", "dateUpdated": "2026-08-17T05:43:37.508Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T05:43:37.508Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\neth: fbnic: don't cache shinfo across skb realloc\n\nfbnic_tx_lso() calls skb_cow_head() which may reallocate the skb\nincluding the shared info. We can't use the pointer calculated\nbefore the call.\n\n BUG: KASAN: slab-use-after-free in fbnic_tx_lso.isra.0+0x668/0x8e0\n Read of size 4 at addr ff110000262edd98 by task swapper/5/0\n Call Trace:\n fbnic_tx_lso.isra.0+0x668/0x8e0\n fbnic_xmit_frame+0x622/0xba0\n dev_hard_start_xmit+0xf4/0x620\n\n Allocated by task 8653:\n __alloc_skb+0x11e/0x5f0\n alloc_skb_with_frags+0xcc/0x6c0\n sock_alloc_send_pskb+0x327/0x3f0\n __ip_append_data+0x188b/0x47a0\n ip_make_skb+0x24a/0x300\n udp_sendmsg+0x14d2/0x21e0\n\n Freed by task 0:\n kfree+0x123/0x5a0\n pskb_expand_head+0x36c/0xfa0\n fbnic_tx_lso.isra.0+0x500/0x8e0\n fbnic_xmit_frame+0x622/0xba0\n dev_hard_start_xmit+0xf4/0x620\n sch_direct_xmit+0x25b/0x1100\n\n The buggy address belongs to the object at ff110000262edc40\n which belongs to the cache skbuff_small_head of size 640\n The buggy address is located 344 bytes inside of\n freed 640-byte region [ff110000262edc40, ff110000262ede" } ], "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 bug is in fbnic_tx_lso on the outbound netdev path; KASAN shows udp_sendmsg→ip_make_skb→dev_hard_start_xmit. Remote peers can trigger GSO/USO/TSO transmits on internet-facing Meta hosts with fbnic (TCP responses or UDP USO), reaching the vulnerable driver without local access.\nAC:L - The USO selftest reliably reproduces the UAF when sending UDP_SEGMENT GSO skbs; attackers control MSS, payload size, and timing to force skb_cow_head/pskb_expand_head to reallocate the skb, making the stale shinfo dereference repeatable rather than dependent on uncontrollable state.\nPR:N - Triggering requires only standard unprivileged socket sendmsg with GSO/USO offload on a host using fbnic, or causing such outbound segmented traffic as an unauthenticated remote client; no CAP_NET_ADMIN, root, or special credentials are needed along the traced path.\nUI:N - Exploitation is fully attacker-driven through crafted network traffic or socket operations; no victim click, mount, or other voluntary action is required beyond normal always-on network service operation.\nS:U - Impact is kernel slab corruption and crash/privilege escalation within the host kernel security domain; it does not cross a VM/hypervisor or IOMMU boundary into a separate security authority.\nC:H - KASAN reports a slab use-after-free with a 4-byte read from freed skb_shared_info after pskb_expand_head; UAF of shinfo fields (gso_type, gso_size, gso_segs) enables heap grooming and arbitrary kernel memory disclosure.\nI:H - Use-after-free of skb_shared_info in the transmit LSO path is memory corruption in attacker-influenced heap objects; stale shinfo values drive metadata and checksum updates, enabling control of kernel data and potential code execution primitives.\nA:H - The reported KASAN slab-use-after-free in fbnic_tx_lso causes kernel oops/panic on transmit; repeated GSO/USO/TSO packets can crash or hang the system, denying availability on affected fbnic-equipped servers." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/ethernet/meta/fbnic/fbnic_txrx.c" ], "versions": [ { "version": "b0b0f52042acb324cd39fbefb2b1ae83af8f8ae1", "lessThan": "83df3e2594cd78aa40b1246a19879abb4891945b", "status": "affected", "versionType": "git" }, { "version": "b0b0f52042acb324cd39fbefb2b1ae83af8f8ae1", "lessThan": "21f304c2aae46625e050c28d979f4b9d83faa85e", "status": "affected", "versionType": "git" }, { "version": "b0b0f52042acb324cd39fbefb2b1ae83af8f8ae1", "lessThan": "62b68b774f06bf52e329f254f0199bc43d350ccf", "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/meta/fbnic/fbnic_txrx.c" ], "versions": [ { "version": "6.15", "status": "affected" }, { "version": "0", "lessThan": "6.15", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "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": "6.15", "versionEndExcluding": "6.18.40" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/83df3e2594cd78aa40b1246a19879abb4891945b" }, { "url": "https://git.kernel.org/stable/c/21f304c2aae46625e050c28d979f4b9d83faa85e" }, { "url": "https://git.kernel.org/stable/c/62b68b774f06bf52e329f254f0199bc43d350ccf" } ], "title": "eth: fbnic: don't cache shinfo across skb realloc", "x_generator": { "engine": "bippy-1.2.0" } } } }