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CVE-2021-47559 (GCVE-0-2021-47559)

Vulnerability from cvelistv5 – Published: 2024-05-24 15:12 – Updated: 2026-08-05 08:48
VLAI
Title
net/smc: Fix NULL pointer dereferencing in smc_vlan_by_tcpsk()
Summary
In the Linux kernel, the following vulnerability has been resolved: net/smc: Fix NULL pointer dereferencing in smc_vlan_by_tcpsk() Coverity reports a possible NULL dereferencing problem: in smc_vlan_by_tcpsk(): 6. returned_null: netdev_lower_get_next returns NULL (checked 29 out of 30 times). 7. var_assigned: Assigning: ndev = NULL return value from netdev_lower_get_next. 1623 ndev = (struct net_device *)netdev_lower_get_next(ndev, &lower); CID 1468509 (#1 of 1): Dereference null return value (NULL_RETURNS) 8. dereference: Dereferencing a pointer that might be NULL ndev when calling is_vlan_dev. 1624 if (is_vlan_dev(ndev)) { Remove the manual implementation and use netdev_walk_all_lower_dev() to iterate over the lower devices. While on it remove an obsolete function parameter comment.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2024-05-24 19:14 UTC
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: cb9d43f6775457cac75544bc4197f26ac2b6f294 , < c94cbd262b6aa3b54d73a1ed1f9c0d19df57f4ff (git)
Affected: cb9d43f6775457cac75544bc4197f26ac2b6f294 , < bb851d0fb02547d03cd40106b5f2391c4fed6ed1 (git)
Affected: cb9d43f6775457cac75544bc4197f26ac2b6f294 , < 587acad41f1bc48e16f42bb2aca63bf323380be8 (git)
guessed Create a notification for this product.
Linux Linux Affected: 4.18
Unaffected: 0 , < 4.18 (semver)
Unaffected: 5.10.83 , ≤ 5.10.* (semver)
Unaffected: 5.15.6 , ≤ 5.15.* (semver)
Unaffected: 5.16 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
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              "impactScore": 3.6,
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      "product_status:fixed": "164",
      "product_status:known_affected": "156",
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      "title": "kernel: net/smc: Fix NULL pointer dereferencing in smc_vlan_by_tcpsk()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-47559.json",
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      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2021-47559.json",
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                  "value": "AV:N - smc_vlan_by_tcpsk() runs on the SMC server listen path (smc_listen_work \u2192 smc_listen_find_device) during the CLC handshake over TCP after a remote peer connects to an AF_SMC listener, matching other SMC listen-path remote scores.\nAC:L - A remote peer only needs to complete a TCP connect with the SMC option and send a CLC proposal; stacked netdev topologies (bond/VLAN) are the intended, common deployment this walker exists for, so the attacker can trigger the path at will.\nPR:N - The CLC handshake runs before any application authentication and SMC performs no peer credential checks, so an unauthenticated remote client needs no account or capability on the target.\nUI:N - smc_listen_work runs automatically on inbound SMC/TCP connections with no additional victim action required beyond an already-listening SMC service.\nS:U - A successful trigger only oopses the local host kernel within the same security authority and does not cross a VM, IOMMU, or other boundary.\nC:N - This is a pure NULL pointer dereference of the netdev_lower_get_next() return in is_vlan_dev(), with no out-of-bounds read, UAF, or other information-disclosure primitive.\nI:N - The fault is a straight NULL dereference crash with no write primitive, type confusion, or memory corruption that could alter kernel state or hijack control flow.\nA:H - Dereferencing the NULL net_device pointer in is_vlan_dev() causes a kernel oops/panic and can take down the system, which is High availability impact."
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        "datePublished": "2024-05-24T15:12:48.675Z",
        "dateReserved": "2024-05-24T15:11:00.727Z",
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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.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.