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net: extend IPv6 exthdr detection of tunneled packets

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: net: extend IPv6 exthdr detection of tunneled packets Commit c4336a07eb6b ("net: correctly handle tunneled traffic on IPV6_CSUM GSO fallback") split skb_gso_has_extension_hdr() into mutually exclusive branches on skb->encapsulation. This did not yet address all paths: 1. With skb->encapsulation set, the outer header is not checked. IPv6 tunnels such as ip6_gre and ip6_tunnel add an outer Destination Options header by default (encap_limit). Their GSO packets skip software GSO, then skb_csum_hwoffload_help() sees the outer extension header and calls skb_checksum_help() on the GSO skb, which warns and drops it. 2. Tunnels over IPv6 without an outer transport header, such as ip6_tunnel, leave skb->transport_header at the inner transport header. skb_network_header_len() then spans the outer IPv6, tunnel and inner IP headers, a false positive. 3. UDP tunnels without an inner network header, such as SCTP-in-UDP or PSP, have no inner IPv6 header to check. Decide on the outer header alone. 4. Directly dereferencing inner_ip_hdr(skb)->version without skb_header_pointer() is unsafe. Instead, check ipv6_ext_hdr(nexthdr) on the outer IPv6 header and, if set, on the inner IPv6 header. Read the headers with skb_header_pointer(). Keep the skb_network_header_len() check when !skb->encapsulation to also catch encapsulated packets without skb->encapsulation (e.g., virtio). Use the same helper in skb_csum_hwoffload_help(). Its o

Announced Source revision 1
Original source ↗

CVE-2026-98852

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-2026-98852

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": "ed71cf465c75f5688b07a35d373cd1d6b589c8ea",
        "lessThan": "fdbd83c2d929ec968b37d2f75149a79440e328ff",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "33670f780e0120c3dacda188c512bbffe0b6044c",
        "lessThan": "44ba9dc568c878b699d05e7cf699572dc9df4b59",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "a98b78116a27e2a57b696b569b2cb431c95cf9b6",
        "lessThan": "aa480f05aed7a9eee87d4a6fc90647fe9679c670",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c4336a07eb6b2526dc2b62928b5104b41a7f81f5",
        "lessThan": "cabacdf98e09eb74599c4d97d7bd7fd659598fb7",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c4336a07eb6b2526dc2b62928b5104b41a7f81f5",
        "lessThan": "5f0764cb1c81a9712bce605d38efe6d844a70b29",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "2094a7cf91b71367b649f991aacc7b579f793d0b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "732fdeb2987c94b439d51f5cb9addddc2fc48c42",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "6.6.134",
        "lessThan": "6.6.160",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "6.12.81",
        "lessThan": "6.12.113",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "6.18.22",
        "lessThan": "6.18.56",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "6.1.168",
        "lessThan": "6.2",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "6.19.12",
        "lessThan": "6.20",
        "versionType": "semver"
      }
    ],
    "programFiles": [
      "net/core/dev.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "7.0"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "7.0",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.6.160",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.113",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.56",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.10",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/core/dev.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-98852

Source reference: /cveMetadata/cveId

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No explicit severity was provided.

Event
#49007 · Revision 1
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