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CVE-2026-80838 (GCVE-0-2026-80838)

Vulnerability from cvelistv5 – Published: 2026-09-04 15:54 – Updated: 2026-09-04 15:54
VLAI
Title
vxlan: keep the last remote linked during FDB flush
Summary
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
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f , < 2a7c2f00843225d5f037676bca649321f3d024c7 (git)
Affected: c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f , < a8820c8a7718327e96849782033e7c85a0f6bcfe (git)
Affected: c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f , < 8ba68fd6cdd1e3c92b92f25c7e48bf7bd51a183c (git)
Affected: c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f , < 4bbc76ee1b21d3bd045d6d819b2bacd30a6372ab (git)
Affected: c499fccb71cb85902b5c5b9ce9c9ae6683e54a8f , < d5d4a7b538b52db63927773a8905fcd9f78a42e2 (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.7
Unaffected: 0 , < 6.7 (semver)
Unaffected: 6.12.108 , ≤ 6.12.* (semver)
Unaffected: 6.18.49 , ≤ 6.18.* (semver)
Unaffected: 7.1.13 , ≤ 7.1.* (semver)
Unaffected: 7.2.3 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/vxlan/vxlan_core.c"
          ],
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          ],
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          "vendor": "Linux",
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              "status": "unaffected",
              "version": "7.2.3",
              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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              "cpeMatch": [
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              "negate": false,
              "operator": "OR"
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      ],
      "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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-04T15:54:48.371Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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        },
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        },
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          "url": "https://git.kernel.org/stable/c/4bbc76ee1b21d3bd045d6d819b2bacd30a6372ab"
        },
        {
          "url": "https://git.kernel.org/stable/c/d5d4a7b538b52db63927773a8905fcd9f78a42e2"
        }
      ],
      "title": "vxlan: keep the last remote linked during FDB flush",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80838",
    "datePublished": "2026-09-04T15:54:48.371Z",
    "dateReserved": "2026-08-26T14:34:25.796Z",
    "dateUpdated": "2026-09-04T15:54:48.371Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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      "date": "2026-09-15",
      "epss": "0.00168",
      "percentile": "0.0641"
    },
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    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-10T01:50:52Z",
      "cve": "CVE-2026-80838",
      "id": "CVE-2026-80838",
      "initial_release_date": "2026-09-05T00:26:27Z",
      "product_status:known_affected": "17",
      "product_status:known_not_affected": "324",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-80838",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-80838.json",
      "version": "4"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.