CVE-2026-64121 (GCVE-0-2026-64121)

Vulnerability from cvelistv5 – Published: 2026-07-19 15:40 – Updated: 2026-07-19 15:40
VLAI
Title
net: ifb: report ethtool stats over num_tx_queues
Summary
In the Linux kernel, the following vulnerability has been resolved: net: ifb: report ethtool stats over num_tx_queues ifb_dev_init() allocates dp->tx_private to dev->num_tx_queues entries via kzalloc_objs(*txp, dev->num_tx_queues). Both IFB per-queue RX and TX stats live in those entries: ifb_xmit() updates txp->rx_stats using the skb queue mapping, ifb_ri_tasklet() updates txp->tx_stats, and ifb_stats64() aggregates both over dev->num_tx_queues. The ethtool stats callbacks instead size and walk the per-queue stats with dev->real_num_rx_queues and dev->real_num_tx_queues. With an asymmetric device where the RX queue count exceeds the TX queue count, for example: ip link add name ifb10 numtxqueues 1 numrxqueues 8 type ifb ethtool -S ifb10 ifb_get_ethtool_stats() indexes past the tx_private allocation and copies adjacent slab data through ETHTOOL_GSTATS. Use dev->num_tx_queues consistently for the stats strings, the stats count, and the stats data walks. This reports one RX stats group and one TX stats group for each backing ifb_q_private entry, which is the queue set IFB can actually populate. Reproduced under UML+KASAN at v7.1-rc2: BUG: KASAN: slab-out-of-bounds in ifb_fill_stats_data+0x3c/0xae Read of size 8 at addr 0000000062dbd228 by task ethtool/36 ifb_fill_stats_data+0x3c/0xae ifb_get_ethtool_stats+0xc0/0x129 __dev_ethtool+0x1ca5/0x363c dev_ethtool+0x123/0x1b3 dev_ioctl+0x56c/0x744 sock_do_ioctl+0x15f/0x1b2 sock_ioctl+0x4d5/0x50a sys_ioctl+0xd8b/0xde9 With the patch applied, the same UML+KASAN repro is silent and ethtool -S ifb10 reports only the stats backed by the single allocated tx_private entry.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: a21ee5b2fcb8d6d3973446c5039e966c4cfe40d1 , < 6afdb8113cb007f9332f59a9b7fd45731b8a9de5 (git)
Affected: a21ee5b2fcb8d6d3973446c5039e966c4cfe40d1 , < 16bd798cb6d8337d7c3eea1adc412f31b5181d5b (git)
Affected: a21ee5b2fcb8d6d3973446c5039e966c4cfe40d1 , < 301a554e458e2f5ec47f2c336a7cb03b877f9fd6 (git)
Affected: a21ee5b2fcb8d6d3973446c5039e966c4cfe40d1 , < f8a5a76b4a683043c6eff2a060bcaa17f9316ad5 (git)
Affected: a21ee5b2fcb8d6d3973446c5039e966c4cfe40d1 , < 2638e1773904d7aa8f24c6e7fda2ed7d69df6fa4 (git)
Affected: a21ee5b2fcb8d6d3973446c5039e966c4cfe40d1 , < 5db89c99566fc4728cc92e941d8e1975711e24b5 (git)
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Linux Linux Affected: 5.17
Unaffected: 0 , < 5.17 (semver)
Unaffected: 6.1.175 , ≤ 6.1.* (semver)
Unaffected: 6.6.142 , ≤ 6.6.* (semver)
Unaffected: 6.12.92 , ≤ 6.12.* (semver)
Unaffected: 6.18.34 , ≤ 6.18.* (semver)
Unaffected: 7.0.11 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
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{
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ifb: report ethtool stats over num_tx_queues\n\nifb_dev_init() allocates dp-\u003etx_private to dev-\u003enum_tx_queues\nentries via kzalloc_objs(*txp, dev-\u003enum_tx_queues). Both IFB\nper-queue RX and TX stats live in those entries: ifb_xmit() updates\ntxp-\u003erx_stats using the skb queue mapping, ifb_ri_tasklet() updates\ntxp-\u003etx_stats, and ifb_stats64() aggregates both over\ndev-\u003enum_tx_queues.\n\nThe ethtool stats callbacks instead size and walk the per-queue\nstats with dev-\u003ereal_num_rx_queues and dev-\u003ereal_num_tx_queues. With\nan asymmetric device where the RX queue count exceeds the TX queue\ncount, for example:\n\n    ip link add name ifb10 numtxqueues 1 numrxqueues 8 type ifb\n    ethtool -S ifb10\n\nifb_get_ethtool_stats() indexes past the tx_private allocation and\ncopies adjacent slab data through ETHTOOL_GSTATS.\n\nUse dev-\u003enum_tx_queues consistently for the stats strings, the\nstats count, and the stats data walks. This reports one RX stats\ngroup and one TX stats group for each backing ifb_q_private entry,\nwhich is the queue set IFB can actually populate.\n\nReproduced under UML+KASAN at v7.1-rc2:\n\n  BUG: KASAN: slab-out-of-bounds in ifb_fill_stats_data+0x3c/0xae\n  Read of size 8 at addr 0000000062dbd228 by task ethtool/36\n  ifb_fill_stats_data+0x3c/0xae\n  ifb_get_ethtool_stats+0xc0/0x129\n  __dev_ethtool+0x1ca5/0x363c\n  dev_ethtool+0x123/0x1b3\n  dev_ioctl+0x56c/0x744\n  sock_do_ioctl+0x15f/0x1b2\n  sock_ioctl+0x4d5/0x50a\n  sys_ioctl+0xd8b/0xde9\n\nWith the patch applied, the same UML+KASAN repro is silent and\nethtool -S ifb10 reports only the stats backed by the single\nallocated tx_private entry."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-19T15:40:19.745Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/16bd798cb6d8337d7c3eea1adc412f31b5181d5b"
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        },
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          "url": "https://git.kernel.org/stable/c/5db89c99566fc4728cc92e941d8e1975711e24b5"
        }
      ],
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64121",
    "datePublished": "2026-07-19T15:40:19.745Z",
    "dateReserved": "2026-07-19T07:54:57.036Z",
    "dateUpdated": "2026-07-19T15:40:19.745Z",
    "state": "PUBLISHED"
  },
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      "date": "2026-07-21",
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      "percentile": "0.06914"
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With\\nan asymmetric device where the RX queue count exceeds the TX queue\\ncount, for example:\\n\\n    ip link add name ifb10 numtxqueues 1 numrxqueues 8 type ifb\\n    ethtool -S ifb10\\n\\nifb_get_ethtool_stats() indexes past the tx_private allocation and\\ncopies adjacent slab data through ETHTOOL_GSTATS.\\n\\nUse dev-\u003enum_tx_queues consistently for the stats strings, the\\nstats count, and the stats data walks. This reports one RX stats\\ngroup and one TX stats group for each backing ifb_q_private entry,\\nwhich is the queue set IFB can actually populate.\\n\\nReproduced under UML+KASAN at v7.1-rc2:\\n\\n  BUG: KASAN: slab-out-of-bounds in ifb_fill_stats_data+0x3c/0xae\\n  Read of size 8 at addr 0000000062dbd228 by task ethtool/36\\n  ifb_fill_stats_data+0x3c/0xae\\n  ifb_get_ethtool_stats+0xc0/0x129\\n  __dev_ethtool+0x1ca5/0x363c\\n  dev_ethtool+0x123/0x1b3\\n  dev_ioctl+0x56c/0x744\\n  sock_do_ioctl+0x15f/0x1b2\\n  sock_ioctl+0x4d5/0x50a\\n  sys_ioctl+0xd8b/0xde9\\n\\nWith the patch applied, the same UML+KASAN repro is silent and\\nethtool -S ifb10 reports only the stats backed by the single\\nallocated tx_private entry.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"drivers/net/ifb.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"a21ee5b2fcb8d6d3973446c5039e966c4cfe40d1\",\"lessThan\":\"6afdb8113cb007f9332f59a9b7fd45731b8a9de5\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"a21ee5b2fcb8d6d3973446c5039e966c4cfe40d1\",\"lessThan\":\"16bd798cb6d8337d7c3eea1adc412f31b5181d5b\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"a21ee5b2fcb8d6d3973446c5039e966c4cfe40d1\",\"lessThan\":\"301a554e458e2f5ec47f2c336a7cb03b877f9fd6\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"a21ee5b2fcb8d6d3973446c5039e966c4cfe40d1\",\"lessThan\":\"f8a5a76b4a683043c6eff2a060bcaa17f9316ad5\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"a21ee5b2fcb8d6d3973446c5039e966c4cfe40d1\",\"lessThan\":\"2638e1773904d7aa8f24c6e7fda2ed7d69df6fa4\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"a21ee5b2fcb8d6d3973446c5039e966c4cfe40d1\",\"lessThan\":\"5db89c99566fc4728cc92e941d8e1975711e24b5\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"drivers/net/ifb.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"5.17\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"5.17\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.175\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.142\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.92\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.34\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.0.11\",\"lessThanOrEqual\":\"7.0.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/16bd798cb6d8337d7c3eea1adc412f31b5181d5b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/2638e1773904d7aa8f24c6e7fda2ed7d69df6fa4\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/301a554e458e2f5ec47f2c336a7cb03b877f9fd6\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/5db89c99566fc4728cc92e941d8e1975711e24b5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/6afdb8113cb007f9332f59a9b7fd45731b8a9de5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/f8a5a76b4a683043c6eff2a060bcaa17f9316ad5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-07-20T11:37:09+00:00",
      "cve": "CVE-2026-64121",
      "id": "CVE-2026-64121",
      "initial_release_date": "2026-07-19T00:00:00+00:00",
      "product_status:known_affected": "246",
      "product_status:known_not_affected": "29",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: net: ifb: report ethtool stats over num_tx_queues",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-64121.json",
      "version": "3"
    }
  }
}



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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.

Sightings

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Nomenclature

  • 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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Detection rules are retrieved from Rulezet.