Vulnerability-Lookup

GHSA-677C-PQCW-QH84

Vulnerability from github – Published: 2024-06-19 15:30 – Updated: 2024-11-01 15:31

Details

In the Linux kernel, the following vulnerability has been resolved:

mptcp: clear 'kern' flag from fallback sockets

The mptcp ULP extension relies on sk->sk_sock_kern being set correctly: It prevents setsockopt(fd, IPPROTO_TCP, TCP_ULP, "mptcp", 6); from working for plain tcp sockets (any userspace-exposed socket).

But in case of fallback, accept() can return a plain tcp sk. In such case, sk is still tagged as 'kernel' and setsockopt will work.

This will crash the kernel, The subflow extension has a NULL ctx->conn mptcp socket:

BUG: KASAN: null-ptr-deref in subflow_data_ready+0x181/0x2b0 Call Trace: tcp_data_ready+0xf8/0x370 [..]

Severity

5.5 (Medium)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2021-47593"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-476"
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    "github_reviewed_at": null,
    "nvd_published_at": "2024-06-19T15:15:53Z",
    "severity": "MODERATE"
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  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: clear \u0027kern\u0027 flag from fallback sockets\n\nThe mptcp ULP extension relies on sk-\u003esk_sock_kern being set correctly:\nIt prevents setsockopt(fd, IPPROTO_TCP, TCP_ULP, \"mptcp\", 6); from\nworking for plain tcp sockets (any userspace-exposed socket).\n\nBut in case of fallback, accept() can return a plain tcp sk.\nIn such case, sk is still tagged as \u0027kernel\u0027 and setsockopt will work.\n\nThis will crash the kernel, The subflow extension has a NULL ctx-\u003econn\nmptcp socket:\n\nBUG: KASAN: null-ptr-deref in subflow_data_ready+0x181/0x2b0\nCall Trace:\n tcp_data_ready+0xf8/0x370\n [..]",
  "id": "GHSA-677c-pqcw-qh84",
  "modified": "2024-11-01T15:31:45Z",
  "published": "2024-06-19T15:30:55Z",
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CVE-2021-47593 (GCVE-0-2021-47593)

Vulnerability from cvelistv5 – Published: 2024-06-19 14:53 – Updated: 2026-05-11 13:57

Title

mptcp: clear 'kern' flag from fallback sockets

Summary

In the Linux kernel, the following vulnerability has been resolved: mptcp: clear 'kern' flag from fallback sockets The mptcp ULP extension relies on sk->sk_sock_kern being set correctly: It prevents setsockopt(fd, IPPROTO_TCP, TCP_ULP, "mptcp", 6); from working for plain tcp sockets (any userspace-exposed socket). But in case of fallback, accept() can return a plain tcp sk. In such case, sk is still tagged as 'kernel' and setsockopt will work. This will crash the kernel, The subflow extension has a NULL ctx->conn mptcp socket: BUG: KASAN: null-ptr-deref in subflow_data_ready+0x181/0x2b0 Call Trace: tcp_data_ready+0xf8/0x370 [..]

Severity

No CVSS data available.

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2024-09-10 17:12 UTC

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/451f1eded7f56e93a…
https://git.kernel.org/stable/c/c26ac0ea3a91c210c…
https://git.kernel.org/stable/c/d6692b3b97bdc165d…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: cf7da0d66cc1a2a19fc5930bb746ffbb2d4cd1be , < 451f1eded7f56e93aaf52eb547ba97742d9c0e97 (git) Affected: cf7da0d66cc1a2a19fc5930bb746ffbb2d4cd1be , < c26ac0ea3a91c210cf90452e625dc441adf3e549 (git) Affected: cf7da0d66cc1a2a19fc5930bb746ffbb2d4cd1be , < d6692b3b97bdc165d150f4c1505751a323a80717 (git)
Linux	Linux	Affected: 5.6 Unaffected: 0 , < 5.6 (semver) Unaffected: 5.10.88 , ≤ 5.10.* (semver) Unaffected: 5.15.11 , ≤ 5.15.* (semver) Unaffected: 5.16 , ≤ * (original_commit_for_fix)

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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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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