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net: remove CAP_SYS_RAWIO zero-padding in dev_validate_header

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: net: remove CAP_SYS_RAWIO zero-padding in dev_validate_header dev_validate_header() reads dev->hard_header_len directly when zero-padding short link layer headers for CAP_SYS_RAWIO holders: if (capable(CAP_SYS_RAWIO)) { memset(ll_header + len, 0, dev->hard_header_len - len); return true; } Packet send paths call dev_validate_header() on skbs whose headroom was allocated from an earlier hard_header_len read. If the device is reconfigured so that dev->hard_header_len increases before validation, the memset writes past the reserved buffer, an out-of-bounds write. This out-of-bounds write is masked in some SOCK_RAW paths today because the same concurrent increase can first make skb_push() exceed the reserved headroom and trigger skb_under_panic(). Remove the zero-padding branch before making those hard_header_len reads consistent, so the snapshot fixes do not turn a loud panic into a silent overwrite. This path is only reached for variable length L2 protocols, where len < hard_header_len but len >= min_header_len. No remaining in-tree variable length L2 protocol implements header_ops->validate, and the CAP_SYS_RAWIO bypass that zero-pads and accepts short headers has no real value beyond allowing testing of intentionally malformed input. Drop the CAP_SYS_RAWIO branch. The remaining reads of dev->hard_header_len in dev_validate_header() are comparisons only and have no memory safety impact.

Announced Source revision 1
Original source ↗

CVE-2026-80731

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-80731

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
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        "status": "affected",
        "version": "b5518429e70cd783b8ca52335456172c1a0589f6",
        "lessThan": "53fd7f912c0877647d6a1e1877f5ea8535ee0b4a",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "2793a23aacbd754dbbb5cb75093deb7e4103bace",
        "lessThan": "fa6d98dd925e72fc028b26a0cbbff9d2f0601ff6",
        "versionType": "git"
      },
      {
        "status": "affected",
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        "lessThan": "8fc9816404166a90ed8d544dc52482fafffb6d9f",
        "versionType": "git"
      },
      {
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      {
        "status": "affected",
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        "versionType": "git"
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      {
        "status": "affected",
        "version": "8b8d278aa4de9335682bbd4a3bb619af015c859e",
        "versionType": "git"
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      {
        "status": "affected",
        "version": "6804052fa9d86e9a512c88b24a5debbfc1a490fc",
        "versionType": "git"
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        "status": "affected",
        "version": "3.2.80",
        "lessThan": "3.2.81",
        "versionType": "semver"
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        "status": "affected",
        "version": "3.16.36",
        "lessThan": "3.17",
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      {
        "status": "affected",
        "version": "4.1.28",
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      {
        "status": "affected",
        "version": "4.4.8",
        "lessThan": "4.5",
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      {
        "status": "affected",
        "version": "4.5.2",
        "lessThan": "4.6",
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      }
    ],
    "programFiles": [
      "include/linux/netdevice.h"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
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        "version": "0",
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        "status": "unaffected",
        "version": "3.2.81",
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        "lessThanOrEqual": "3.2.*"
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      {
        "status": "unaffected",
        "version": "5.10.265",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.216",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.183",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.152",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.104",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.45",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.1.9",
        "versionType": "semver",
        "lessThanOrEqual": "7.1.*"
      },
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        "status": "unaffected",
        "version": "7.2",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "include/linux/netdevice.h"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-80731

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#34372 · Revision 1
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Publisher date
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