{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2021-46998", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-02-27T18:42:55.950Z", "datePublished": "2024-02-28T08:13:21.651Z", "dateUpdated": "2026-08-05T08:45:27.902Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T08:45:27.902Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nethernet:enic: Fix a use after free bug in enic_hard_start_xmit\n\nIn enic_hard_start_xmit, it calls enic_queue_wq_skb(). Inside\nenic_queue_wq_skb, if some error happens, the skb will be freed\nby dev_kfree_skb(skb). But the freed skb is still used in\nskb_tx_timestamp(skb).\n\nMy patch makes enic_queue_wq_skb() return error and goto spin_unlock()\nincase of error. The solution is provided by Govind.\nSee https://lkml.org/lkml/2021/4/30/961." } ], "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 - The UAF is in enic ndo_start_xmit (enic_hard_start_xmit → enic_queue_wq_skb → skb_tx_timestamp), reached when a local process transmits via ordinary socket send over an enic netdev; remote peers do not enter this TX-prepare path.\nAC:L - Once DMA mapping fails, the free-then-skb_tx_timestamp UAF is deterministic with no race; a local attacker can induce mapping failure by exhausting swiotlb/IOMMU resources, which is within attacker influence.\nPR:L - Any unprivileged local user can send packets out an up enic interface through the generic networking stack; no CAP_NET_ADMIN or other capability is required on the transmit path.\nUI:N - The attacker triggers the TX path and resource exhaustion themselves via their own send syscalls; no victim action is required.\nS:U - This is a standard in-kernel skb heap UAF enabling local privilege escalation within the same kernel security authority, with no VM, IOMMU, or sandbox boundary crossed.\nC:H - Use-after-free of the skb (skb_shinfo/tx_flags access, and skb_tstamp_tx when SKBTX_SW_TSTAMP is set) allows heap spraying and reuse of the freed object, enabling arbitrary kernel memory disclosure primitives.\nI:H - The same skb UAF enables heap corruption and write/control-flow hijack primitives after reclaim, per UAF exploitation guidance.\nA:H - Accessing the freed skb in skb_tx_timestamp reliably causes kernel oops/panic even without a full exploit." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/ethernet/cisco/enic/enic_main.c" ], "versions": [ { "version": "fb7516d42478ebc8e2f00efb76ef96f7b68fd8d3", "lessThan": "25a87b1f566b5eb2af2857a928f0e2310d900976", "status": "affected", "versionType": "git" }, { "version": "fb7516d42478ebc8e2f00efb76ef96f7b68fd8d3", "lessThan": "f7f6f07774091a6ddd98500b85386c3c6afb30d3", "status": "affected", "versionType": "git" }, { "version": "fb7516d42478ebc8e2f00efb76ef96f7b68fd8d3", "lessThan": "7afdd6aba95c8a526038e7abe283eeac3e4320f1", "status": "affected", "versionType": "git" }, { "version": "fb7516d42478ebc8e2f00efb76ef96f7b68fd8d3", "lessThan": "6892396ebf04ea2c021d80e10f4075e014cd7cc3", "status": "affected", "versionType": "git" }, { "version": "fb7516d42478ebc8e2f00efb76ef96f7b68fd8d3", "lessThan": "d90529392aaf498dafa95d212295d64b2cea4e24", "status": "affected", "versionType": "git" }, { "version": "fb7516d42478ebc8e2f00efb76ef96f7b68fd8d3", "lessThan": "643001b47adc844ae33510c4bb93c236667008a3", "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/cisco/enic/enic_main.c" ], "versions": [ { "version": "4.16", "status": "affected" }, { "version": "0", "lessThan": "4.16", "status": "unaffected", "versionType": "semver" }, { "version": "4.19.191", "lessThanOrEqual": "4.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.120", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.38", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.11.22", "lessThanOrEqual": "5.11.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.12.5", "lessThanOrEqual": "5.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.13", "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": "4.16", "versionEndExcluding": "4.19.191" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "5.4.120" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "5.10.38" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "5.11.22" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "5.12.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.16", "versionEndExcluding": "5.13" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/25a87b1f566b5eb2af2857a928f0e2310d900976" }, { "url": "https://git.kernel.org/stable/c/f7f6f07774091a6ddd98500b85386c3c6afb30d3" }, { "url": "https://git.kernel.org/stable/c/7afdd6aba95c8a526038e7abe283eeac3e4320f1" }, { "url": "https://git.kernel.org/stable/c/6892396ebf04ea2c021d80e10f4075e014cd7cc3" }, { "url": "https://git.kernel.org/stable/c/d90529392aaf498dafa95d212295d64b2cea4e24" }, { "url": "https://git.kernel.org/stable/c/643001b47adc844ae33510c4bb93c236667008a3" } ], "title": "ethernet:enic: Fix a use after free bug in enic_hard_start_xmit", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-04T05:24:38.462Z" }, "title": "CVE Program Container", "references": [ { "url": "https://git.kernel.org/stable/c/25a87b1f566b5eb2af2857a928f0e2310d900976", "tags": [ "x_transferred" ] }, { "url": 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"dateUpdated": "2024-09-11T17:33:36.196Z" } } ] } }