CVE-2026-43329 (GCVE-0-2026-43329)

Vulnerability from cvelistv5 – Published: 2026-05-08 13:31 – Updated: 2026-05-08 13:31
VLAI?
Title
netfilter: flowtable: strictly check for maximum number of actions
Summary
In the Linux kernel, the following vulnerability has been resolved: netfilter: flowtable: strictly check for maximum number of actions The maximum number of flowtable hardware offload actions in IPv6 is: * ethernet mangling (4 payload actions, 2 for each ethernet address) * SNAT (4 payload actions) * DNAT (4 payload actions) * Double VLAN (4 vlan actions, 2 for popping vlan, and 2 for pushing) for QinQ. * Redirect (1 action) Which makes 17, while the maximum is 16. But act_ct supports for tunnels actions too. Note that payload action operates at 32-bit word level, so mangling an IPv6 address takes 4 payload actions. Update flow_action_entry_next() calls to check for the maximum number of supported actions. While at it, rise the maximum number of actions per flow from 16 to 24 so this works fine with IPv6 setups.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: c29f74e0df7a02b8303bcdce93a7c0132d62577a , < ead66c77303f760f6c30be96e2e20d5a77cef614 (git)
Affected: c29f74e0df7a02b8303bcdce93a7c0132d62577a , < fe9018d3e94329f1951b00805a8640bc06f56ead (git)
Affected: c29f74e0df7a02b8303bcdce93a7c0132d62577a , < 5382bb03e9c33b089d60788478b922a2dca284cc (git)
Affected: c29f74e0df7a02b8303bcdce93a7c0132d62577a , < 57c78bd2e2dd08897acd35b2bf8bcef322e36f5e (git)
Affected: c29f74e0df7a02b8303bcdce93a7c0132d62577a , < 504c9456699dcf4d15195ef34a0fa94a80bfc877 (git)
Affected: c29f74e0df7a02b8303bcdce93a7c0132d62577a , < 879959a7a2be814dd57568655eafa3d8f4d0309e (git)
Affected: c29f74e0df7a02b8303bcdce93a7c0132d62577a , < 76522fcdbc3a02b568f5d957f7e66fc194abb893 (git)
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    Linux Linux Affected: 5.5
Unaffected: 0 , < 5.5 (semver)
Unaffected: 5.15.203 , ≤ 5.15.* (semver)
Unaffected: 6.1.168 , ≤ 6.1.* (semver)
Unaffected: 6.6.134 , ≤ 6.6.* (semver)
Unaffected: 6.12.81 , ≤ 6.12.* (semver)
Unaffected: 6.18.22 , ≤ 6.18.* (semver)
Unaffected: 6.19.12 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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          "programFiles": [
            "net/netfilter/nf_flow_table_offload.c"
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: flowtable: strictly check for maximum number of actions\n\nThe maximum number of flowtable hardware offload actions in IPv6 is:\n\n* ethernet mangling (4 payload actions, 2 for each ethernet address)\n* SNAT (4 payload actions)\n* DNAT (4 payload actions)\n* Double VLAN (4 vlan actions, 2 for popping vlan, and 2 for pushing)\n  for QinQ.\n* Redirect (1 action)\n\nWhich makes 17, while the maximum is 16. But act_ct supports for tunnels\nactions too. Note that payload action operates at 32-bit word level, so\nmangling an IPv6 address takes 4 payload actions.\n\nUpdate flow_action_entry_next() calls to check for the maximum number of\nsupported actions.\n\nWhile at it, rise the maximum number of actions per flow from 16 to 24\nso this works fine with IPv6 setups."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-08T13:31:17.479Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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    "dateReserved": "2026-05-01T14:12:56.002Z",
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  }
}


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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

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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.