CVE-2025-40043 (GCVE-0-2025-40043)

Vulnerability from cvelistv5 – Published: 2025-10-28 11:48 – Updated: 2026-08-05 12:07
VLAI
Title
net: nfc: nci: Add parameter validation for packet data
Summary
In the Linux kernel, the following vulnerability has been resolved: net: nfc: nci: Add parameter validation for packet data Syzbot reported an uninitialized value bug in nci_init_req, which was introduced by commit 5aca7966d2a7 ("Merge tag 'perf-tools-fixes-for-v6.17-2025-09-16' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools"). This bug arises due to very limited and poor input validation that was done at nic_valid_size(). This validation only validates the skb->len (directly reflects size provided at the userspace interface) with the length provided in the buffer itself (interpreted as NCI_HEADER). This leads to the processing of memory content at the address assuming the correct layout per what opcode requires there. This leads to the accesses to buffer of `skb_buff->data` which is not assigned anything yet. Following the same silent drop of packets of invalid sizes at `nic_valid_size()`, add validation of the data in the respective handlers and return error values in case of failure. Release the skb if error values are returned from handlers in `nci_nft_packet` and effectively do a silent drop Possible TODO: because we silently drop the packets, the call to `nci_request` will be waiting for completion of request and will face timeouts. These timeouts can get excessively logged in the dmesg. A proper handling of them may require to export `nci_request_cancel` (or propagate error handling from the nft packets handlers).
Severity
8.8 (High)
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 6a2968aaf50c7a22fced77a5e24aa636281efca8 , < 8fcc7315a10a84264e55bb65ede10f0af20a983f (git)
Affected: 6a2968aaf50c7a22fced77a5e24aa636281efca8 , < bfdda0123dde406dbff62e7e9136037e97998a15 (git)
Affected: 6a2968aaf50c7a22fced77a5e24aa636281efca8 , < 0ba68bea1e356f466ad29449938bea12f5f3711f (git)
Affected: 6a2968aaf50c7a22fced77a5e24aa636281efca8 , < 74837bca0748763a77f77db47a0bdbe63b347628 (git)
Affected: 6a2968aaf50c7a22fced77a5e24aa636281efca8 , < c395d1e548cc68e84584ffa2e3ca9796a78bf7b9 (git)
Affected: 6a2968aaf50c7a22fced77a5e24aa636281efca8 , < 9c328f54741bd5465ca1dc717c84c04242fac2e1 (git)
guessed Create a notification for this product.
Linux Linux Affected: 3.2
Unaffected: 0 , < 3.2 (semver)
Unaffected: 5.15.195 , ≤ 5.15.* (semver)
Unaffected: 6.1.156 , ≤ 6.1.* (semver)
Unaffected: 6.6.112 , ≤ 6.6.* (semver)
Unaffected: 6.12.53 , ≤ 6.12.* (semver)
Unaffected: 6.17.3 , ≤ 6.17.* (semver)
Unaffected: 6.18 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
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        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: nfc: nci: Add parameter validation for packet data\n\nSyzbot reported an uninitialized value bug in nci_init_req, which was\nintroduced by commit 5aca7966d2a7 (\"Merge tag\n\u0027perf-tools-fixes-for-v6.17-2025-09-16\u0027 of\ngit://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools\").\n\nThis bug arises due to very limited and poor input validation\nthat was done at nic_valid_size(). This validation only\nvalidates the skb-\u003elen (directly reflects size provided at the\nuserspace interface) with the length provided in the buffer\nitself (interpreted as NCI_HEADER). This leads to the processing\nof memory content at the address assuming the correct layout\nper what opcode requires there. This leads to the accesses to\nbuffer of `skb_buff-\u003edata` which is not assigned anything yet.\n\nFollowing the same silent drop of packets of invalid sizes at\n`nic_valid_size()`, add validation of the data in the respective\nhandlers and return error values in case of failure. Release\nthe skb if error values are returned from handlers in\n`nci_nft_packet` and effectively do a silent drop\n\nPossible TODO: because we silently drop the packets, the\ncall to `nci_request` will be waiting for completion of request\nand will face timeouts. These timeouts can get excessively logged\nin the dmesg. A proper handling of them may require to export\n`nci_request_cancel` (or propagate error handling from the\nnft packets handlers)."
        }
      ],
      "metrics": [
        {
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            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
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              "lang": "en",
              "value": "AV:A - The parsed data is NCI notification payload whose RF-specific and activation parameters (ATS/RATS length byte, ATR_RES length, tech-specific params) originate from the contactless peer, so an attacker with a spoofed card or NFC emulator in proximity of a phone/POS/embedded reader supplies the malformed lengths. NFC proximity is Adjacent per kernel scoring guidance (a local unprivileged N_NCI-ldisc path also exists, but is strictly lower severity).\nAC:L - The attacker directly controls the length byte versus actual payload length and can present the malformed card/frame repeatedly until the target polls it; no race, no unpredictable memory-layout precondition is required.\nPR:N - No credentials or account on the target are needed \u2014 NFC polling activates and parses the notification automatically, and on the local variant `NCIUARTSETDRIVER` in nci_uart_tty_ioctl() has no capability check at all.\nUI:N - The NFC stack polls and processes discovery/activation notifications autonomously; the attacker brings the hostile device into range and the victim performs no action.\nS:U - The over-read, the write-back in the credits handler, and the leaked data all stay within the kernel\u0027s own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - Tens of bytes past the payload \u2014 uninitialized slab tailroom and skb_shared_info, which holds kernel pointers \u2014 are copied into nfcid1/sens_res/ATS and exported to userspace via NFC netlink attributes, yielding stale-heap and kernel-pointer disclosure usable for KASLR defeat.\nI:H - `nci_core_conn_credits_ntf_packet()` writes masked bytes back into memory beyond the validated payload for up to 10 entries and adds an out-of-bounds byte into conn_info-\u003ecredits_cnt, and unvalidated data populates ndev state (nci_ver, manufact_id, remote_gb, credits), giving attacker-shapeable kernel memory/state corruption.\nA:H - Out-of-bounds slab reads can hit a redzone/adjacent object and oops (KASAN/panic_on_oops), and the commit itself notes the resulting dropped packets leave nci_request() blocking until timeout with repeated dmesg flooding, degrading the NFC stack."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:07:16.234Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/8fcc7315a10a84264e55bb65ede10f0af20a983f"
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          "url": "https://git.kernel.org/stable/c/bfdda0123dde406dbff62e7e9136037e97998a15"
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        },
        {
          "url": "https://git.kernel.org/stable/c/9c328f54741bd5465ca1dc717c84c04242fac2e1"
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      ],
      "title": "net: nfc: nci: Add parameter validation for packet data",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2025-40043",
    "datePublished": "2025-10-28T11:48:22.230Z",
    "dateReserved": "2025-04-16T07:20:57.154Z",
    "dateUpdated": "2026-08-05T12:07:16.234Z",
    "state": "PUBLISHED"
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      "date": "2026-09-26",
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                "versions": [
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                    "version": "3.2"
                  },
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        "descriptions": [
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            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: nfc: nci: Add parameter validation for packet data\n\nSyzbot reported an uninitialized value bug in nci_init_req, which was\nintroduced by commit 5aca7966d2a7 (\"Merge tag\n\u0027perf-tools-fixes-for-v6.17-2025-09-16\u0027 of\ngit://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools\").\n\nThis bug arises due to very limited and poor input validation\nthat was done at nic_valid_size(). This validation only\nvalidates the skb-\u003elen (directly reflects size provided at the\nuserspace interface) with the length provided in the buffer\nitself (interpreted as NCI_HEADER). This leads to the processing\nof memory content at the address assuming the correct layout\nper what opcode requires there. This leads to the accesses to\nbuffer of `skb_buff-\u003edata` which is not assigned anything yet.\n\nFollowing the same silent drop of packets of invalid sizes at\n`nic_valid_size()`, add validation of the data in the respective\nhandlers and return error values in case of failure. Release\nthe skb if error values are returned from handlers in\n`nci_nft_packet` and effectively do a silent drop\n\nPossible TODO: because we silently drop the packets, the\ncall to `nci_request` will be waiting for completion of request\nand will face timeouts. These timeouts can get excessively logged\nin the dmesg. A proper handling of them may require to export\n`nci_request_cancel` (or propagate error handling from the\nnft packets handlers)."
          }
        ],
        "id": "CVE-2025-40043",
        "lastModified": "2026-07-30T06:24:07.647",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "ADJACENT_NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 8.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
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              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            }
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        "published": "2025-10-28T12:15:38.333",
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            "url": "https://git.kernel.org/stable/c/9c328f54741bd5465ca1dc717c84c04242fac2e1"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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          },
          {
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            "url": "https://git.kernel.org/stable/c/c395d1e548cc68e84584ffa2e3ca9796a78bf7b9"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Deferred"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "None",
      "current_release_date": "2026-06-30T10:25:39+00:00",
      "cve": "CVE-2025-40043",
      "id": "CVE-2025-40043",
      "initial_release_date": "2025-10-28T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: net: nfc: nci: Add parameter validation for packet data",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-40043.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-12T16:47:27Z",
      "cve": "CVE-2025-40043",
      "id": "CVE-2025-40043",
      "initial_release_date": "2025-10-29T00:25:25Z",
      "product_status:first_fixed": "2",
      "product_status:known_affected": "712",
      "product_status:known_not_affected": "66",
      "product_status:recommended": "470",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2025-40043",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2025-40043.json",
      "version": "43"
    }
  }
}



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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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