CVE-2026-98794 (GCVE-0-2026-98794)
Vulnerability from cvelistv5
Published
2026-10-18 15:48
Modified
2026-10-21 12:57
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
Impacted products
Vendor Product Version
Linux Linux Version: 87375ab47cd0ba04124c6d3fd80db5c368f5dcb6
Version: 87375ab47cd0ba04124c6d3fd80db5c368f5dcb6
Version: 87375ab47cd0ba04124c6d3fd80db5c368f5dcb6
Version: 87375ab47cd0ba04124c6d3fd80db5c368f5dcb6
Version: 87375ab47cd0ba04124c6d3fd80db5c368f5dcb6
 Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "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": "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": "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"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.160",
                  "versionStartIncluding": "2.6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.113",
                  "versionStartIncluding": "2.6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.56",
                  "versionStartIncluding": "2.6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.10",
                  "versionStartIncluding": "2.6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "2.6.14",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-21T12:57:03.851Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/d7d33c9efa9d1a2f244a1a64ec9b540b0f8975a0"
        },
        {
          "url": "https://git.kernel.org/stable/c/f4cd1db7d421e82945713a36084bb0c35b75b27e"
        },
        {
          "url": "https://git.kernel.org/stable/c/55d033324f67a15ff56be6d38d6e87f644e0ed62"
        },
        {
          "url": "https://git.kernel.org/stable/c/45a93111835ccfea7d969ec73588e33745fd9834"
        },
        {
          "url": "https://git.kernel.org/stable/c/f96e91748f6304668fe647e686d199d7207d36f1"
        }
      ],
      "title": "ipvs: filter some flags received in the backup server",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98794",
    "datePublished": "2026-10-18T15:48:37.924Z",
    "dateReserved": "2026-09-25T10:25:14.370Z",
    "dateUpdated": "2026-10-21T12:57:03.851Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.