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CVE-2021-46998 (GCVE-0-2021-46998)

Vulnerability from cvelistv5 – Published: 2024-02-28 08:13 – Updated: 2026-08-05 08:45
VLAI
Title
ethernet:enic: Fix a use after free bug in enic_hard_start_xmit
Summary
In the Linux kernel, the following vulnerability has been resolved: ethernet:enic: Fix a use after free bug in enic_hard_start_xmit In enic_hard_start_xmit, it calls enic_queue_wq_skb(). Inside enic_queue_wq_skb, if some error happens, the skb will be freed by dev_kfree_skb(skb). But the freed skb is still used in skb_tx_timestamp(skb). My patch makes enic_queue_wq_skb() return error and goto spin_unlock() incase of error. The solution is provided by Govind. See https://lkml.org/lkml/2021/4/30/961.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2024-09-10 16:00 UTC
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: fb7516d42478ebc8e2f00efb76ef96f7b68fd8d3 , < 25a87b1f566b5eb2af2857a928f0e2310d900976 (git)
Affected: fb7516d42478ebc8e2f00efb76ef96f7b68fd8d3 , < f7f6f07774091a6ddd98500b85386c3c6afb30d3 (git)
Affected: fb7516d42478ebc8e2f00efb76ef96f7b68fd8d3 , < 7afdd6aba95c8a526038e7abe283eeac3e4320f1 (git)
Affected: fb7516d42478ebc8e2f00efb76ef96f7b68fd8d3 , < 6892396ebf04ea2c021d80e10f4075e014cd7cc3 (git)
Affected: fb7516d42478ebc8e2f00efb76ef96f7b68fd8d3 , < d90529392aaf498dafa95d212295d64b2cea4e24 (git)
Affected: fb7516d42478ebc8e2f00efb76ef96f7b68fd8d3 , < 643001b47adc844ae33510c4bb93c236667008a3 (git)
guessed Create a notification for this product.
Linux Linux Affected: 4.16
Unaffected: 0 , < 4.16 (semver)
Unaffected: 4.19.191 , ≤ 4.19.* (semver)
Unaffected: 5.4.120 , ≤ 5.4.* (semver)
Unaffected: 5.10.38 , ≤ 5.10.* (semver)
Unaffected: 5.11.22 , ≤ 5.11.* (semver)
Unaffected: 5.12.5 , ≤ 5.12.* (semver)
Unaffected: 5.13 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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En enic_hard_start_xmit, llama a enic_queue_wq_skb(). Dentro de enic_queue_wq_skb, si ocurre alg\u00fan error, dev_kfree_skb(skb) liberar\u00e1 el skb. Pero el skb liberado todav\u00eda se usa en skb_tx_timestamp(skb). Mi parche hace que enic_queue_wq_skb() devuelva un error y vaya a spin_unlock() en caso de error. La soluci\u00f3n la proporciona Govind. Consulte 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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-04T20:06:18+00:00",
      "cve": "CVE-2021-46998",
      "id": "CVE-2021-46998",
      "initial_release_date": "2021-01-01T00:00:00+00:00",
      "product_status:known_affected": "42",
      "product_status:known_not_affected": "156",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ethernet:enic: Fix a use after free bug in enic_hard_start_xmit",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-46998.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-09T00:38:55Z",
      "cve": "CVE-2021-46998",
      "id": "CVE-2021-46998",
      "initial_release_date": "2024-03-01T04:07:58Z",
      "product_status:known_affected": "388",
      "product_status:known_not_affected": "270",
      "product_status:recommended": "207",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2021-46998",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2021-46998.json",
      "version": "53"
    },
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CVE Program Container\", \"references\": [{\"url\": \"https://git.kernel.org/stable/c/25a87b1f566b5eb2af2857a928f0e2310d900976\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/f7f6f07774091a6ddd98500b85386c3c6afb30d3\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/7afdd6aba95c8a526038e7abe283eeac3e4320f1\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/6892396ebf04ea2c021d80e10f4075e014cd7cc3\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/d90529392aaf498dafa95d212295d64b2cea4e24\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://git.kernel.org/stable/c/643001b47adc844ae33510c4bb93c236667008a3\", \"tags\": [\"x_transferred\"]}], \"providerMetadata\": {\"orgId\": \"af854a3a-2127-422b-91ae-364da2661108\", \"shortName\": \"CVE\", \"dateUpdated\": \"2024-08-04T05:24:38.462Z\"}}, {\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2021-46998\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2024-09-10T16:00:51.946004Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2024-09-11T12:42:17.576Z\"}}], \"cna\": {\"title\": \"ethernet:enic: Fix a use after free bug in enic_hard_start_xmit\", \"metrics\": [{\"cvssV3_1\": {\"version\": \"3.1\", \"baseScore\": 7.8, \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"AV:L - The UAF is in enic ndo_start_xmit (enic_hard_start_xmit \\u2192 enic_queue_wq_skb \\u2192 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\": [{\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"fb7516d42478ebc8e2f00efb76ef96f7b68fd8d3\", \"lessThan\": \"25a87b1f566b5eb2af2857a928f0e2310d900976\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"fb7516d42478ebc8e2f00efb76ef96f7b68fd8d3\", \"lessThan\": \"f7f6f07774091a6ddd98500b85386c3c6afb30d3\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"fb7516d42478ebc8e2f00efb76ef96f7b68fd8d3\", \"lessThan\": \"7afdd6aba95c8a526038e7abe283eeac3e4320f1\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"fb7516d42478ebc8e2f00efb76ef96f7b68fd8d3\", \"lessThan\": \"6892396ebf04ea2c021d80e10f4075e014cd7cc3\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"fb7516d42478ebc8e2f00efb76ef96f7b68fd8d3\", \"lessThan\": \"d90529392aaf498dafa95d212295d64b2cea4e24\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"fb7516d42478ebc8e2f00efb76ef96f7b68fd8d3\", \"lessThan\": \"643001b47adc844ae33510c4bb93c236667008a3\", \"versionType\": \"git\"}], \"programFiles\": [\"drivers/net/ethernet/cisco/enic/enic_main.c\"], \"defaultStatus\": \"unaffected\"}, {\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"4.16\"}, {\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"4.16\", \"versionType\": \"semver\"}, {\"status\": \"unaffected\", \"version\": \"4.19.191\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"4.19.*\"}, {\"status\": \"unaffected\", \"version\": \"5.4.120\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.4.*\"}, {\"status\": \"unaffected\", \"version\": \"5.10.38\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.10.*\"}, {\"status\": \"unaffected\", \"version\": \"5.11.22\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.11.*\"}, {\"status\": \"unaffected\", \"version\": \"5.12.5\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.12.*\"}, {\"status\": \"unaffected\", \"version\": \"5.13\", \"versionType\": \"original_commit_for_fix\", \"lessThanOrEqual\": \"*\"}], \"programFiles\": [\"drivers/net/ethernet/cisco/enic/enic_main.c\"], \"defaultStatus\": \"affected\"}], \"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\"}], \"x_generator\": {\"engine\": \"bippy-1.2.0\"}, \"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.\"}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"4.19.191\", \"versionStartIncluding\": \"4.16\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.4.120\", \"versionStartIncluding\": \"4.16\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.10.38\", \"versionStartIncluding\": \"4.16\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.11.22\", \"versionStartIncluding\": \"4.16\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.12.5\", \"versionStartIncluding\": \"4.16\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.13\", \"versionStartIncluding\": \"4.16\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2026-08-05T08:45:27.902Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2021-46998\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-08-05T08:45:27.902Z\", \"dateReserved\": \"2024-02-27T18:42:55.950Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2024-02-28T08:13:21.651Z\", \"assignerShortName\": \"Linux\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


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