CVE-2026-43373 (GCVE-0-2026-43373)
Vulnerability from cvelistv5
Published
2026-05-08 14:21
Modified
2026-08-05 12:27
Severity ?
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: net: ncsi: fix skb leak in error paths Early return paths in NCSI RX and AEN handlers fail to release the received skb, resulting in a memory leak. Specifically, ncsi_aen_handler() returns on invalid AEN packets without consuming the skb. Similarly, ncsi_rcv_rsp() exits early when failing to resolve the NCSI device, response handler, or request, leaving the skb unfreed.
References
Impacted products
Vendor Product Version
Linux Linux Version: 138635cc27c9737f940c3aa80912ff7a61c825af
Version: 138635cc27c9737f940c3aa80912ff7a61c825af
Version: 138635cc27c9737f940c3aa80912ff7a61c825af
Version: 138635cc27c9737f940c3aa80912ff7a61c825af
Version: 138635cc27c9737f940c3aa80912ff7a61c825af
Version: 138635cc27c9737f940c3aa80912ff7a61c825af
Version: 138635cc27c9737f940c3aa80912ff7a61c825af
Version: 138635cc27c9737f940c3aa80912ff7a61c825af
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/ncsi/ncsi-aen.c",
            "net/ncsi/ncsi-rsp.c"
          ],
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          "vendor": "Linux",
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          "vendor": "Linux",
          "versions": [
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              "version": "4.8"
            },
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "5.10.253",
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            {
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              "status": "unaffected",
              "version": "5.15.203",
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              "version": "6.6.130",
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              "version": "6.18.19",
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              "status": "unaffected",
              "version": "6.19.9",
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            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.253",
                  "versionStartIncluding": "4.8",
                  "vulnerable": true
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                  "versionStartIncluding": "4.8",
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                  "versionEndExcluding": "7.0",
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                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ncsi: fix skb leak in error paths\n\nEarly return paths in NCSI RX and AEN handlers fail to release\nthe received skb, resulting in a memory leak.\n\nSpecifically, ncsi_aen_handler() returns on invalid AEN packets\nwithout consuming the skb. Similarly, ncsi_rcv_rsp() exits early\nwhen failing to resolve the NCSI device, response handler, or\nrequest, leaving the skb unfreed."
        }
      ],
      "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 - The vulnerable handlers are reached through the kernel Ethernet receive path for ETH_P_NCSI frames on an NCSI-enabled network device. A remote peer capable of delivering NCSI frames to the management interface can trigger the bug with network packets.\nAC:L - Triggering only requires malformed or unmatched NCSI response/AEN packets that take deterministic early error paths. No race, timing, or hard-to-control system state is required.\nPR:N - The packet receive path performs no credential, capability, or authentication checks before entering ncsi_rcv_rsp() or ncsi_aen_handler(). Local NCSI netlink operations may require admin permission, but the vulnerable receive path does not.\nUI:N - No victim user action is needed. Packets are processed automatically by the network receive stack.\nS:U - The impact remains within the kernel and the affected NCSI/network device security authority. There is no VM, sandbox, IOMMU, or other cross-scope boundary crossing.\nC:N - The fixed bug is a missing kfree_skb()/consume_skb() on error paths, not an information disclosure. The leaked skb is not exposed back to the attacker.\nI:N - The bug does not corrupt memory or provide a write primitive. It only retains references to received skb objects that should have been freed.\nA:H - Each trigger leaks a received skb, and the attacker can repeat this indefinitely with malformed or unmatched NCSI packets. On plausible BMC/management-controller deployments this can exhaust kernel memory and deny service."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:27:33.592Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/9891d7f4f1ede473c54b49776ae07755083eef06"
        },
        {
          "url": "https://git.kernel.org/stable/c/fef5aa6e3bcf3c8053307642663a63b7362d7552"
        },
        {
          "url": "https://git.kernel.org/stable/c/81d6aee32f8f7bbc175c05dbf61f4430bfb88c4a"
        },
        {
          "url": "https://git.kernel.org/stable/c/59962588197863d0d746879f193905c0c6b3df49"
        },
        {
          "url": "https://git.kernel.org/stable/c/553366c271479c0d571dd1bb5d1bcde4747fb82e"
        },
        {
          "url": "https://git.kernel.org/stable/c/b70c4e5e711931cdd56e6e905737b72f1e649189"
        },
        {
          "url": "https://git.kernel.org/stable/c/87138dde2d6937b12b967f28fe598a7d59000ae4"
        },
        {
          "url": "https://git.kernel.org/stable/c/5c3398a54266541610c8d0a7082e654e9ff3e259"
        }
      ],
      "title": "net: ncsi: fix skb leak in error paths",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43373",
    "datePublished": "2026-05-08T14:21:23.875Z",
    "dateReserved": "2026-05-01T14:12:56.006Z",
    "dateUpdated": "2026-08-05T12:27:33.592Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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