CVE-2026-74724 (GCVE-0-2026-74724)
Vulnerability from cvelistv5
Published
2026-08-22 15:33
Modified
2026-08-25 05:42
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: ipvs: avoid out-of-bounds write in ip_vs_nat_icmp Sashiko warns that local attacker can modify the packet while it is processed by IPVS. Some places read the IP ihl field multiple times which can cause out-of-bounds access. One such place is ip_vs_nat_icmp where we can write after the validated area. Fix it by providing ciph argument just like it is done for IPv6 and use ciph->len as offset to the embedded transport header. Modify some IPv4 header checks by reading the ihl field only once.
References
Impacted products
Vendor Product Version
Linux Linux Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
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{
  "containers": {
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/net/ip_vs.h",
            "net/netfilter/ipvs/ip_vs_core.c",
            "net/netfilter/ipvs/ip_vs_xmit.c"
          ],
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          "product": "Linux",
          "programFiles": [
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            "net/netfilter/ipvs/ip_vs_core.c",
            "net/netfilter/ipvs/ip_vs_xmit.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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              "version": "7.1.9",
              "versionType": "semver"
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            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.183",
                  "versionStartIncluding": "2.6.12",
                  "vulnerable": true
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              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipvs: avoid out-of-bounds write in ip_vs_nat_icmp\n\nSashiko warns that local attacker can modify the packet\nwhile it is processed by IPVS. Some places read the\nIP ihl field multiple times which can cause out-of-bounds\naccess. One such place is ip_vs_nat_icmp where we\ncan write after the validated area.\n\nFix it by providing ciph argument just like it is done for\nIPv6 and use ciph-\u003elen as offset to the embedded transport\nheader.\n\nModify some IPv4 header checks by reading the ihl field\nonly once."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The OOB write in ip_vs_nat_icmp() requires a local process to change the embedded IPv4 ihl in skb frags between ip_vs_fill_iph_skb_icmp() validation and the NAT write; remote-only ICMP to IPVS netfilter hooks cannot perform that TOCTOU without local access to the packet buffer.\nAC:L - A local attacker controls both sides of the race by concurrently injecting ICMP errors with TCP/UDP/SCTP payloads matching an IPVS NAT connection and modifying the embedded header ihl in skb frags during softirq processing; no victim-specific state or uncontrollable heap layout is required.\nPR:L - Triggering requires a local account able to race skb frag modification (e.g., via raw/packet sockets with CAP_NET_RAW, obtainable in a user namespace) against IPVS ICMP NAT handling on a host where IPVS is already configured; no init-namespace root is needed.\nUI:N - No victim user interaction is required; exploitation is driven entirely by attacker-controlled local packet injection and concurrent frag modification while IPVS processes ICMP errors on NAT-mode connections through LOCAL_IN, LOCAL_OUT, or FORWARD hooks.\nS:U - The out-of-bounds write corrupts kernel skb memory on the IPVS load-balancer host within the same kernel security authority; it does not cross VM, container, or IOMMU boundaries into a separate security scope.\nC:H - Writing TCP/UDP/SCTP port fields and running ip_send_check() using a re-read inflated ihl corrupts skb data beyond the validated region; out-of-bounds kernel memory corruption is exploitable for information disclosure and heap layout control.\nI:H - The bug is an out-of-bounds write of 16-bit port values (and checksum updates over an attacker-inflated header length) past skb_ensure_writable()\u0027s bound, enabling adjacent kernel memory corruption and potential control-flow hijacking on internet-facing IPVS NAT nodes.\nA:H - Corrupting skb header memory beyond the ensured writable area can cause kernel oops or panic during ICMP NAT mangling; a local attacker can repeatedly trigger the race on kube-proxy IPVS nodes and hardware load balancers running IPVS NAT mode."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-25T05:42:04.705Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/3b8f79af0e98f27b932b0b416e9c52b692d31ff9"
        },
        {
          "url": "https://git.kernel.org/stable/c/3c779b258c9c3c3567af68d4f45c2f751f35bd0e"
        },
        {
          "url": "https://git.kernel.org/stable/c/be65fa324640c7a95e30b146159a2be5cc73f22e"
        },
        {
          "url": "https://git.kernel.org/stable/c/a69a4b3fff5814d079beff9a1e9d369994b2ed47"
        },
        {
          "url": "https://git.kernel.org/stable/c/243d0187ec4c3837b9b0004f18d1068e46115760"
        },
        {
          "url": "https://git.kernel.org/stable/c/646922a0379496154e8c8faca4f8e2fd9100cacc"
        }
      ],
      "title": "ipvs: avoid out-of-bounds write in ip_vs_nat_icmp",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74724",
    "datePublished": "2026-08-22T15:33:15.832Z",
    "dateReserved": "2026-08-15T05:44:03.929Z",
    "dateUpdated": "2026-08-25T05:42:04.705Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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