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vxlan: initialize _md in vxlan_xmit_one()

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: vxlan: initialize _md in vxlan_xmit_one() If a VXLAN device is configured with both VXLAN_F_COLLECT_METADATA and VXLAN_F_GBP, and a packet is transmitted through it using an external ip_tunnel_info that lacks the IP_TUNNEL_VXLAN_OPT_BIT flag, md is left pointing to the uninitialized _md stack variable: if (test_bit(IP_TUNNEL_VXLAN_OPT_BIT, info->key.tun_flags)) { if (info->options_len < sizeof(*md)) goto drop; md = ip_tunnel_info_opts(info); } Because IP_TUNNEL_VXLAN_OPT_BIT is not set, md is not updated and remains pointing to _md. Later, vxlan_build_skb() is called with md, which eventually calls vxlan_build_gbp_hdr(): if (vxflags & VXLAN_F_GBP) vxlan_build_gbp_hdr(vxh, md); Inside vxlan_build_gbp_hdr(), md->gbp is read: if (!md->gbp) return; gbp = (struct vxlanhdr_gbp *)vxh; ... if (md->gbp & VXLAN_GBP_DONT_LEARN) gbp->dont_learn = 1; If the stack contains garbage, this causes: 1) VXLAN_HF_GBP flag to be spuriously set in the VXLAN header. 2) gbp->dont_learn and gbp->policy_applied to be set from stack bits. 3) gbp->policy_id to receive 16 bits of uninitialized kernel stack data, leaking it onto the wire. Fix this by zero-initializing _md. If IP_TUNNEL_VXLAN_OPT_BIT is not present, md->gbp remains 0, and vxlan_build_gbp_hdr() returns early without modifying the VXLAN header.

Announced Source revision 1
Original source ↗

CVE-2026-97965

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-2026-97965

Linux

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

Affected versions
Not stated in this record
Fixed versions
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Prerequisites
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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": [
      {
        "status": "affected",
        "version": "ee122c79d4227f6ec642157834b6a90fcffa4382",
        "lessThan": "fb78beb64e0e79557e4cd7cd17fea744bb6f01d9",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "ee122c79d4227f6ec642157834b6a90fcffa4382",
        "lessThan": "0d13b5a413bffc8718b3821b78537ccc6596c233",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "ee122c79d4227f6ec642157834b6a90fcffa4382",
        "lessThan": "bfb74c48ac2d31476d5e09cf9658844508d2608a",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "ee122c79d4227f6ec642157834b6a90fcffa4382",
        "lessThan": "081f22177d9d12b1e381b787f203cd5f47508187",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "ee122c79d4227f6ec642157834b6a90fcffa4382",
        "lessThan": "be83178bfc44588f6e3adb827ed874c683193466",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "drivers/net/vxlan/vxlan_core.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "4.3"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "4.3",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.6.160",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.111",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.53",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.7",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "drivers/net/vxlan/vxlan_core.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-97965

Source reference: /cveMetadata/cveId

Publisher severity

No explicit severity was provided.

Event
#48819 · Revision 1
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