FKIE_CVE-2026-98794

Vulnerability from fkie_nvd - Published: 2026-10-18 16:17 - Updated: 2026-10-30 13:21
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: ipvs: filter some flags received in the backup server While the IPVS SYNC protocol is not secure by design we can still protect the backup server from messages that can wreak havoc. This commit addresses problems from received connection flags or their combinations. We now drop messages as follows: 1. the NO_CPORT+TEMPLATE combination allows lookups for normal connections to hit template which can break in many ways. While the master does not sync connections with NO_CPORT flag, i.e. before they are established, we still accept NO_CPORT without TEMPLATE. 2. ONE_PACKET: it is not sent by master, so we do not expect it in backup. Before now it was ignored by IP_VS_CONN_F_BACKUP_MASK for protocol v1 while protocol v0 created connections that are not hashed and dropped immediately. Better to apply the IP_VS_CONN_F_BACKUP_MASK also to the flags from v0 messages for consistency with v1.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3a9f5459db60311643bfbadf019f6d5370f2f26a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/438a5335276614186d6a96b8e7bddce811ad4ad6
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/45a93111835ccfea7d969ec73588e33745fd9834
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/55d033324f67a15ff56be6d38d6e87f644e0ed62
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/d7d33c9efa9d1a2f244a1a64ec9b540b0f8975a0
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ef3cd6c0b826e50dc21653b32552e258de6fd51c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f4cd1db7d421e82945713a36084bb0c35b75b27e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f96e91748f6304668fe647e686d199d7207d36f1
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/ipvs/ip_vs_sync.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ef3cd6c0b826e50dc21653b32552e258de6fd51c",
              "status": "affected",
              "version": "87375ab47cd0ba04124c6d3fd80db5c368f5dcb6",
              "versionType": "git"
            },
            {
              "lessThan": "3a9f5459db60311643bfbadf019f6d5370f2f26a",
              "status": "affected",
              "version": "87375ab47cd0ba04124c6d3fd80db5c368f5dcb6",
              "versionType": "git"
            },
            {
              "lessThan": "438a5335276614186d6a96b8e7bddce811ad4ad6",
              "status": "affected",
              "version": "87375ab47cd0ba04124c6d3fd80db5c368f5dcb6",
              "versionType": "git"
            },
            {
              "lessThan": "d7d33c9efa9d1a2f244a1a64ec9b540b0f8975a0",
              "status": "affected",
              "version": "87375ab47cd0ba04124c6d3fd80db5c368f5dcb6",
              "versionType": "git"
            },
            {
              "lessThan": "f4cd1db7d421e82945713a36084bb0c35b75b27e",
              "status": "affected",
              "version": "87375ab47cd0ba04124c6d3fd80db5c368f5dcb6",
              "versionType": "git"
            },
            {
              "lessThan": "55d033324f67a15ff56be6d38d6e87f644e0ed62",
              "status": "affected",
              "version": "87375ab47cd0ba04124c6d3fd80db5c368f5dcb6",
              "versionType": "git"
            },
            {
              "lessThan": "45a93111835ccfea7d969ec73588e33745fd9834",
              "status": "affected",
              "version": "87375ab47cd0ba04124c6d3fd80db5c368f5dcb6",
              "versionType": "git"
            },
            {
              "lessThan": "f96e91748f6304668fe647e686d199d7207d36f1",
              "status": "affected",
              "version": "87375ab47cd0ba04124c6d3fd80db5c368f5dcb6",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/netfilter/ipvs/ip_vs_sync.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.14"
            },
            {
              "lessThan": "2.6.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.273",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.224",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.191",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.160",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.113",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.56",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipvs: filter some flags received in the backup server\n\nWhile the IPVS SYNC protocol is not secure by design\nwe can still protect the backup server from messages that\ncan wreak havoc.\n\nThis commit addresses problems from received connection flags\nor their combinations. We now drop messages as follows:\n\n1. the NO_CPORT+TEMPLATE combination allows lookups for normal\nconnections to hit template which can break in many ways.\nWhile the master does not sync connections with NO_CPORT flag,\ni.e. before they are established, we still accept NO_CPORT\nwithout TEMPLATE.\n\n2. ONE_PACKET: it is not sent by master, so we do not\nexpect it in backup. Before now it was ignored by\nIP_VS_CONN_F_BACKUP_MASK for protocol v1 while protocol\nv0 created connections that are not hashed and dropped\nimmediately. Better to apply the IP_VS_CONN_F_BACKUP_MASK\nalso to the flags from v0 messages for consistency with v1."
    }
  ],
  "id": "CVE-2026-98794",
  "lastModified": "2026-10-30T13:21:28.253",
  "metrics": {},
  "published": "2026-10-18T16:17:33.390",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3a9f5459db60311643bfbadf019f6d5370f2f26a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/438a5335276614186d6a96b8e7bddce811ad4ad6"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/45a93111835ccfea7d969ec73588e33745fd9834"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/55d033324f67a15ff56be6d38d6e87f644e0ed62"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/d7d33c9efa9d1a2f244a1a64ec9b540b0f8975a0"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ef3cd6c0b826e50dc21653b32552e258de6fd51c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f4cd1db7d421e82945713a36084bb0c35b75b27e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f96e91748f6304668fe647e686d199d7207d36f1"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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