CVE-2026-80838

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: vxlan: keep the last remote linked during FDB flush A non-nexthop FDB entry is expected to have at least one remote while it remains reachable through the FDB hash table. A filtered bulk flush violates this invariant when every remote matches: It unlinks the last remote in vxlan_fdb_dst_destroy() and only afterwards tells vxlan_flush() to destroy the parent FDB entry. An RCU reader can find the parent during this interval. first_remote_rcu() then applies list_entry_rcu() to the empty list head, producing an invalid remote pointer that the receive learning path can read from and write to. When a matching remote is the sole remaining remote, leave it linked and ask the caller to destroy the entire FDB entry. vxlan_fdb_destroy() keeps the remote attached while sending the deletion notification and removing the parent from the lookup structures.

Severity

Not scored

CVSS score

Not available

Vulnerability status

Received

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-09-04 16:18:12.183000

Last modified

2026-10-19 09:17:19.120000

View original CVE JSON

{
  "id": "CVE-2026-80838",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-09-04T16:18:12.183",
  "lastModified": "2026-10-19T09:17:19.120",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvxlan: keep the last remote linked during FDB flush\n\nA non-nexthop FDB entry is expected to have at least one remote while it\nremains reachable through the FDB hash table. A filtered bulk flush\nviolates this invariant when every remote matches: It unlinks the last\nremote in vxlan_fdb_dst_destroy() and only afterwards tells vxlan_flush()\nto destroy the parent FDB entry.\n\nAn RCU reader can find the parent during this interval.\nfirst_remote_rcu() then applies list_entry_rcu() to the empty list head,\nproducing an invalid remote pointer that the receive learning path can\nread from and write to.\n\nWhen a matching remote is the sole remaining remote, leave it linked and\nask the caller to destroy the entire FDB entry. vxlan_fdb_destroy() keeps\nthe remote attached while sending the deletion notification and removing\nthe parent from the lookup structures."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "drivers/net/vxlan/vxlan_core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f",
              "lessThan": "2a7c2f00843225d5f037676bca649321f3d024c7",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f",
              "lessThan": "a8820c8a7718327e96849782033e7c85a0f6bcfe",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f",
              "lessThan": "8ba68fd6cdd1e3c92b92f25c7e48bf7bd51a183c",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f",
              "lessThan": "4bbc76ee1b21d3bd045d6d819b2bacd30a6372ab",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f",
              "lessThan": "d5d4a7b538b52db63927773a8905fcd9f78a42e2",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "drivers/net/vxlan/vxlan_core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "6.7",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "6.7",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.12.108",
              "lessThanOrEqual": "6.12.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.49",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.1.13",
              "lessThanOrEqual": "7.1.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2.3",
              "lessThanOrEqual": "7.2.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.3",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/2a7c2f00843225d5f037676bca649321f3d024c7",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/4bbc76ee1b21d3bd045d6d819b2bacd30a6372ab",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/8ba68fd6cdd1e3c92b92f25c7e48bf7bd51a183c",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a8820c8a7718327e96849782033e7c85a0f6bcfe",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d5d4a7b538b52db63927773a8905fcd9f78a42e2",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}