Vulnerability-Lookup

GHSA-82QC-Q32M-354F

Vulnerability from github – Published: 2026-08-27 06:31 – Updated: 2026-08-27 06:31

Details

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

mptcp: reclaim forward-allocated memory on RX path errors

After commit 9db5b3cec4ec ("mptcp: borrow forward memory from subflow"), errors in the receive path prior to queueing skbs into the receive queue do not trigger forward-allocated memory reclaiming.

Prevent forward memory from growing unboundedly in pathological drop scenarios by explicitly reclaiming memory when skbs are dropped.

Severity

7.5 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-80588"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-26T15:17:15Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: reclaim forward-allocated memory on RX path errors\n\nAfter commit 9db5b3cec4ec (\"mptcp: borrow forward memory from subflow\"),\nerrors in the receive path prior to queueing skbs into the receive\nqueue do not trigger forward-allocated memory reclaiming.\n\nPrevent forward memory from growing unboundedly in pathological drop\nscenarios by explicitly reclaiming memory when skbs are dropped.",
  "id": "GHSA-82qc-q32m-354f",
  "modified": "2026-08-27T06:31:33Z",
  "published": "2026-08-27T06:31:33Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80588"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/41b49a8b914ec7dcb03eae93fb27f3c464078644"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/473f1a5ab2abc98dd9e74b95b9c23c66c47535cc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8277f48a06d3aa1441f6d0b6998ccc0360d30ed8"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-80588 (GCVE-0-2026-80588)

Vulnerability from cvelistv5 – Published: 2026-08-26 14:37 – Updated: 2026-08-27 05:02

Title

mptcp: reclaim forward-allocated memory on RX path errors

Summary

In the Linux kernel, the following vulnerability has been resolved: mptcp: reclaim forward-allocated memory on RX path errors After commit 9db5b3cec4ec ("mptcp: borrow forward memory from subflow"), errors in the receive path prior to queueing skbs into the receive queue do not trigger forward-allocated memory reclaiming. Prevent forward memory from growing unboundedly in pathological drop scenarios by explicitly reclaiming memory when skbs are dropped.

Severity

7.5 (High)


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

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/473f1a5ab2abc98dd…
https://git.kernel.org/stable/c/8277f48a06d3aa144…
https://git.kernel.org/stable/c/41b49a8b914ec7dcb…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: a84164847b1e0a106ebc46821e5d2f9b775c9dc8 , < 473f1a5ab2abc98dd9e74b95b9c23c66c47535cc (git) Affected: 9db5b3cec4ec1c0cd3239689f5c8653d691a1754 , < 8277f48a06d3aa1441f6d0b6998ccc0360d30ed8 (git) Affected: 9db5b3cec4ec1c0cd3239689f5c8653d691a1754 , < 41b49a8b914ec7dcb03eae93fb27f3c464078644 (git) Affected: 6.18.35 , < 6.18.46 (semver)
Linux	Linux	Affected: 6.19 Unaffected: 0 , < 6.19 (semver) Unaffected: 6.18.46 , ≤ 6.18.* (semver) Unaffected: 7.1.10 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/mptcp/protocol.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "473f1a5ab2abc98dd9e74b95b9c23c66c47535cc",
              "status": "affected",
              "version": "a84164847b1e0a106ebc46821e5d2f9b775c9dc8",
              "versionType": "git"
            },
            {
              "lessThan": "8277f48a06d3aa1441f6d0b6998ccc0360d30ed8",
              "status": "affected",
              "version": "9db5b3cec4ec1c0cd3239689f5c8653d691a1754",
              "versionType": "git"
            },
            {
              "lessThan": "41b49a8b914ec7dcb03eae93fb27f3c464078644",
              "status": "affected",
              "version": "9db5b3cec4ec1c0cd3239689f5c8653d691a1754",
              "versionType": "git"
            },
            {
              "lessThan": "6.18.46",
              "status": "affected",
              "version": "6.18.35",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/mptcp/protocol.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.19"
            },
            {
              "lessThan": "6.19",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.46",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.46",
                  "versionStartIncluding": "6.18.35",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.10",
                  "versionStartIncluding": "6.19",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.19",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: reclaim forward-allocated memory on RX path errors\n\nAfter commit 9db5b3cec4ec (\"mptcp: borrow forward memory from subflow\"),\nerrors in the receive path prior to queueing skbs into the receive\nqueue do not trigger forward-allocated memory reclaiming.\n\nPrevent forward memory from growing unboundedly in pathological drop\nscenarios by explicitly reclaiming memory when skbs are dropped."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - Remote TCP/MPTCP peers reach the bug on the established-connection RX datapath (tcp_rcv_established \u2192 subflow_data_ready \u2192 mptcp_data_ready \u2192 __mptcp_move_skbs_from_subflow \u2192 __mptcp_move_skb \u2192 mptcp_drop) when duplicate or out-of-window mapped data is dropped before skb_set_owner_r().\nAC:L - The attacker fully controls subflow packet contents and ordering on their MPTCP connection and can deterministically trigger drops (duplicate map_seq, OoO beyond rcv_wnd) on every crafted segment without races, rare sysctl state, or uncontrollable memory layout.\nPR:N - No local account or kernel capability is required on the victim; any remote peer that completes the TCP/MPTCP handshake on an IPPROTO_MPTCP socket (Android clients, MPTCP-enabled servers, curl --mptcp) can flood pathological RX drops without target credentials.\nUI:N - Exploitation needs only attacker-generated MPTCP/TCP traffic on an existing or attacker-initiated connection; no victim mount, file open, click, or other cooperative user action beyond normal network stack processing.\nS:U - Impact is unbounded sk_forward_alloc growth and kernel memory exhaustion on the affected host; it does not cross VM, container, IOMMU, or sandbox boundaries to another security authority.\nC:N - This is a forward-memory accounting leak on skb drop after mptcp_borrow_fwdmem(); skb data is freed and no use-after-free, out-of-bounds read, or other memory-corruption primitive exposes kernel contents to the attacker.\nI:N - The flaw only fails to reclaim borrowed forward allocation when dropping skbs; it does not corrupt, overwrite, or modify attacker-chosen memory and provides no write or code-execution primitive.\nA:H - Each pre-queue drop leaks roughly skb-\u003etruesize forward memory while bypassing the removed sk_rmem_schedule guard, so a remote peer can repeatedly trigger unbounded per-connection kernel memory growth and OOM denial of service, matching CNA precedent for repeatable network skb/memory leaks."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-27T05:02:09.335Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/473f1a5ab2abc98dd9e74b95b9c23c66c47535cc"
        },
        {
          "url": "https://git.kernel.org/stable/c/8277f48a06d3aa1441f6d0b6998ccc0360d30ed8"
        },
        {
          "url": "https://git.kernel.org/stable/c/41b49a8b914ec7dcb03eae93fb27f3c464078644"
        }
      ],
      "title": "mptcp: reclaim forward-allocated memory on RX path errors",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80588",
    "datePublished": "2026-08-26T14:37:42.685Z",
    "dateReserved": "2026-08-26T14:34:25.770Z",
    "dateUpdated": "2026-08-27T05:02:09.335Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

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GHSA-82QC-Q32M-354F

CVE-2026-80588 (GCVE-0-2026-80588)

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