CVE-2026-68127 (GCVE-0-2026-68127)
Vulnerability from cvelistv5
Published
2026-08-10 11:58
Modified
2026-08-19 16:29
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: ila: reload IPv6 header after pskb_may_pull in checksum adjust ila_csum_adjust_transport() caches ip6h = ipv6_hdr(skb) before calling pskb_may_pull(). On a non-linear skb whose transport header sits in a page fragment, pskb_may_pull() can call __pskb_pull_tail() / pskb_expand_head() and free the old skb head, leaving ip6h dangling; the following get_csum_diff(ip6h, p) then reads freed memory. ila_update_ipv6_locator() uses ip6h (and the iaddr derived from it) again after the csum-adjust call and additionally writes the new locator through that pointer. Impact: a remote IPv6 packet routed through a configured ILA csum-adjust-transport route or receive-side mapping triggers a slab-use-after-free in ila_update_ipv6_locator() (KASAN). The route or mapping requires CAP_NET_ADMIN to configure, but trigger packets are unauthenticated once it exists. Reload ip6h after each pskb_may_pull() in ila_csum_adjust_transport() before the csum-diff read. In ila_update_ipv6_locator() only the ILA_CSUM_ADJUST_TRANSPORT case pulls the skb, so reload ip6h and iaddr in that case alone before the destination-address write; the neutral-map modes never pull and keep their cached pointers.
Impacted products
Vendor Product Version
Linux Linux Version: 33f11d16142b06588eedfc1dd8cf93790979a712
Version: 33f11d16142b06588eedfc1dd8cf93790979a712
Version: 33f11d16142b06588eedfc1dd8cf93790979a712
Version: 33f11d16142b06588eedfc1dd8cf93790979a712
Version: 33f11d16142b06588eedfc1dd8cf93790979a712
Version: 33f11d16142b06588eedfc1dd8cf93790979a712
Version: 33f11d16142b06588eedfc1dd8cf93790979a712
Version: 33f11d16142b06588eedfc1dd8cf93790979a712
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ipv6/ila/ila_common.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "e451a904606c571f731ef7a06b3398619dce5300",
              "status": "affected",
              "version": "33f11d16142b06588eedfc1dd8cf93790979a712",
              "versionType": "git"
            },
            {
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              "status": "affected",
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              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "33f11d16142b06588eedfc1dd8cf93790979a712",
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              "versionType": "git"
            },
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            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/ipv6/ila/ila_common.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.5"
            },
            {
              "lessThan": "4.5",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.265",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.216",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.183",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.148",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.101",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.42",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.265",
                  "versionStartIncluding": "4.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.216",
                  "versionStartIncluding": "4.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.183",
                  "versionStartIncluding": "4.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.148",
                  "versionStartIncluding": "4.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.101",
                  "versionStartIncluding": "4.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.42",
                  "versionStartIncluding": "4.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.6",
                  "versionStartIncluding": "4.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "4.5",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nila: reload IPv6 header after pskb_may_pull in checksum adjust\n\nila_csum_adjust_transport() caches ip6h = ipv6_hdr(skb) before calling\npskb_may_pull(). On a non-linear skb whose transport header sits in a page\nfragment, pskb_may_pull() can call __pskb_pull_tail() / pskb_expand_head()\nand free the old skb head, leaving ip6h dangling; the following\nget_csum_diff(ip6h, p) then reads freed memory. ila_update_ipv6_locator()\nuses ip6h (and the iaddr derived from it) again after the csum-adjust\ncall and additionally writes the new locator through that pointer.\n\nImpact: a remote IPv6 packet routed through a configured ILA\ncsum-adjust-transport route or receive-side mapping triggers a\nslab-use-after-free in ila_update_ipv6_locator() (KASAN). The route or\nmapping requires CAP_NET_ADMIN to configure, but trigger packets are\nunauthenticated once it exists.\n\nReload ip6h after each pskb_may_pull() in ila_csum_adjust_transport()\nbefore the csum-diff read. In ila_update_ipv6_locator() only the\nILA_CSUM_ADJUST_TRANSPORT case pulls the skb, so reload ip6h and iaddr in\nthat case alone before the destination-address write; the neutral-map\nmodes never pull and keep their cached pointers."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - The bug is reached from ipv6_rcv() through NF_INET_PRE_ROUTING (ila_nf_input) or IPv6 routing/LWT input/output when remote IPv6 packets matching a configured ILA csum-adjust-transport mapping or route are processed; no local syscall is required on internet-facing routers, gateways, or NVO3/overlay hosts.\nAC:L - Once ILA csum-adjust-transport is configured, a remote attacker can reliably send IPv6 TCP/UDP/ICMPv6 packets whose transport headers live in skb page fragments so pskb_may_pull() reallocates the head; they control packet layout and can retry without races or uncontrollable memory layout.\nPR:N - Trigger packets are processed unauthenticated on the network datapath; although ILA routes/mappings require CAP_NET_ADMIN to install, that is operator infrastructure (also obtainable in a user netns), not a privilege the remote attacker needs to send the malformed IPv6 packets that hit ila_update_ipv6_locator().\nUI:N - No victim user action is required beyond normal IPv6 packet delivery; exploitation is fully automated once the affected ILA configuration exists and the attacker sends crafted packets to the host.\nS:U - The slab use-after-free corrupts kernel packet-processing memory within the host kernel security authority; it is not a VM escape, container breakout, or IOMMU/DMA boundary bypass.\nC:H - ila_csum_adjust_transport() reads the cached IPv6 header via get_csum_diff(ip6h, p) after pskb_may_pull() frees the old skb head, causing a slab use-after-free read of freed memory that can disclose kernel heap contents.\nI:H - ila_update_ipv6_locator() then writes iaddr-\u003eloc = p-\u003elocator through the same stale iaddr pointer derived from the freed header, giving a slab use-after-free write primitive that can be leveraged for arbitrary memory corruption and control-flow hijacking.\nA:H - The freed skb-head slab use-after-free was reproduced under KASAN and can cause kernel oops/panic during IPv6 receive/forwarding; even unsuccessful exploitation typically crashes or destabilizes the host."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-19T16:29:41.771Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/e451a904606c571f731ef7a06b3398619dce5300"
        },
        {
          "url": "https://git.kernel.org/stable/c/1eadcb43893b897ade85ac5bf5c618054bc3c655"
        },
        {
          "url": "https://git.kernel.org/stable/c/ba353caafb06ccee57b78d3254e3cebf1dea4a93"
        },
        {
          "url": "https://git.kernel.org/stable/c/896a9512d0d83c2a4b357e5585b7b62a8e3f95c1"
        },
        {
          "url": "https://git.kernel.org/stable/c/7097a0280b178237265681be66d1bef11d15894b"
        },
        {
          "url": "https://git.kernel.org/stable/c/472aba2603ca74c4f7722cb0c0296942b0776b8d"
        },
        {
          "url": "https://git.kernel.org/stable/c/c6a13ae00dab3a1a8c7cf2f843f0fc9e8d4b0ccc"
        },
        {
          "url": "https://git.kernel.org/stable/c/92d3817649df2b0b6a008a686c8275c88d7ef594"
        }
      ],
      "title": "ila: reload IPv6 header after pskb_may_pull in checksum adjust",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-68127",
    "datePublished": "2026-08-10T11:58:48.489Z",
    "dateReserved": "2026-07-30T09:28:09.369Z",
    "dateUpdated": "2026-08-19T16:29:41.771Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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