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CVE-2026-81000 affecting package kernel for versions less than 6.6.157.1-1

Type: advisorySource: OSV1 source record

In the Linux kernel, the following vulnerability has been resolved: net: tun: bound receive headroom tun_get_user() uses tun->align both as skb headroom and when choosing how much packet data to keep linear. OVS can propagate an oversized headroom request from another port to TUN or TAP. When align is larger than the usable space in a one-page skb head, SKB_MAX_HEAD(align) underflows and the result becomes negative when stored in good_linear. That value later wraps when assigned to the size_t linear variable, and tun_alloc_skb() can place skb->data outside the allocated head. Bound the headroom stored by TUN to the one-page skb-head budget and the largest non-sentinel 16-bit skb header offset. Leave one linear byte for raw TUN and a complete Ethernet header for TAP, including NET_IP_ALIGN. Also pull the raw-TUN protocol byte and the TAP Ethernet header before accessing them, so these checks remain safe for nonlinear skbs supplied by other allocation paths.

Announced Source revision 1
Original source ↗

AZL-100232

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: osv:AZL-100232

kernel

Source reference: /affected/0/package/name

Affected versions
Not stated in this record
Fixed versions
6.6.157.1-1

Source reference: /affected/0/ranges

Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          },
          {
            "fixed": "6.6.157.1-1"
          }
        ]
      }
    ],
    "package": {
      "name": "kernel",
      "purl": "pkg:rpm/azure-linux/kernel",
      "ecosystem": "Azure Linux:3"
    },
    "database_specific": {
      "source": "https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-100232.json"
    }
  }
]
Related CVEs
CVE-2026-81000

Source reference: /upstream

Publisher severity

No explicit severity was provided.

Linked CVE context

These ratings describe the referenced vulnerabilities and products. They are not a severity rating for every application using this dependency.

CVE-2026-81000 · High

Linux, Linux

Event
#68079 · Revision 1
Added to Heist Feed
Publisher date
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