Vulnerability-Lookup

FKIE_CVE-2025-21972

Vulnerability from fkie_nvd - Published: 2025-04-01 16:15 - Updated: 2026-07-30 06:22

Severity

8.8 (High) - CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: net: mctp: unshare packets when reassembling Ensure that the frag_list used for reassembly isn't shared with other packets. This avoids incorrect reassembly when packets are cloned, and prevents a memory leak due to circular references between fragments and their skb_shared_info. The upcoming MCTP-over-USB driver uses skb_clone which can trigger the problem - other MCTP drivers don't share SKBs. A kunit test is added to reproduce the issue.

References

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/5c47d5bfa7b096cf8890afac32141c578583f8e0	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/f44fff3d3c6cd67b6f348b821d73c4d6888c7a6e	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/f5d83cf0eeb90fade4d5c4d17d24b8bee9ceeecc	Patch

Impacted products

Vendor	Product	Version
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	6.14
linux	linux_kernel	6.14
linux	linux_kernel	6.14
linux	linux_kernel	6.14
linux	linux_kernel	6.14
linux	linux_kernel	6.14

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/mctp/route.c",
            "net/mctp/test/route-test.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "versionType": "git"
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              "versionType": "git"
            },
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              "versionType": "git"
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        },
        {
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          "product": "Linux",
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            "net/mctp/route.c",
            "net/mctp/test/route-test.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.15"
            },
            {
              "lessThan": "5.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.20",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.13.*",
              "status": "unaffected",
              "version": "6.13.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.14",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
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  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: mctp: unshare packets when reassembling\n\nEnsure that the frag_list used for reassembly isn\u0027t shared with other\npackets. This avoids incorrect reassembly when packets are cloned, and\nprevents a memory leak due to circular references between fragments and\ntheir skb_shared_info.\n\nThe upcoming MCTP-over-USB driver uses skb_clone which can trigger the\nproblem - other MCTP drivers don\u0027t share SKBs.\n\nA kunit test is added to reproduce the issue."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: net: mctp: paquetes no compartidos al reensamblar. Aseg\u00farese de que la lista de fragmentos utilizada para el reensamblado no se comparta con otros paquetes. Esto evita un reensamblado incorrecto al clonar paquetes y previene una fuga de memoria debido a referencias circulares entre fragmentos y su skb_shared_info. El pr\u00f3ximo controlador MCTP sobre USB utiliza skb_clone, lo que puede desencadenar el problema; otros controladores MCTP no comparten los SKB. Se ha a\u00f1adido una prueba kunit para reproducir el problema."
    }
  ],
  "id": "CVE-2025-21972",
  "lastModified": "2026-07-30T06:22:01.147",
  "metrics": {
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      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "ADJACENT_NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
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        },
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        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
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          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
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        "impactScore": 3.6,
        "source": "nvd@nist.gov",
        "type": "Primary"
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  "published": "2025-04-01T16:15:28.540",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
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  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-401"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}

CVE-2025-21972 (GCVE-0-2025-21972)

Vulnerability from cvelistv5 – Published: 2025-04-01 15:47 – Updated: 2026-08-05 11:55

Title

net: mctp: unshare packets when reassembling

Summary

Severity

8.8 (High)


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

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/5c47d5bfa7b096cf8…
https://git.kernel.org/stable/c/f44fff3d3c6cd67b6…
https://git.kernel.org/stable/c/f5d83cf0eeb90fade…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 4a992bbd365094730a31bae1e12a6ca695336d57 , < 5c47d5bfa7b096cf8890afac32141c578583f8e0 (git) Affected: 4a992bbd365094730a31bae1e12a6ca695336d57 , < f44fff3d3c6cd67b6f348b821d73c4d6888c7a6e (git) Affected: 4a992bbd365094730a31bae1e12a6ca695336d57 , < f5d83cf0eeb90fade4d5c4d17d24b8bee9ceeecc (git)
Linux	Linux	Affected: 5.15 Unaffected: 0 , < 5.15 (semver) Unaffected: 6.12.20 , ≤ 6.12.* (semver) Unaffected: 6.13.8 , ≤ 6.13.* (semver) Unaffected: 6.14 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/mctp/route.c",
            "net/mctp/test/route-test.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "5c47d5bfa7b096cf8890afac32141c578583f8e0",
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              "versionType": "git"
            },
            {
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              "status": "affected",
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            },
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              "versionType": "git"
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          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
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            "net/mctp/test/route-test.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "5.15"
            },
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              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.20",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.13.*",
              "status": "unaffected",
              "version": "6.13.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.14",
              "versionType": "original_commit_for_fix"
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              "lang": "en",
              "value": "AV:A - The vulnerable code is a network-stack packet handler (`ETH_P_MCTP` packet_type \u2192 `mctp_route_input`), but MCTP has no internet-routable transport in the kernel \u2014 packets arrive from a device on the local management bus (SMBus/I2C, I3C, USB, serial), a limited administrative domain directly analogous to the Bluetooth/WiFi case.\nAC:L - The attacker fully controls both preconditions: sending a multi-packet (SOM/EOM) fragmented message, and causing the skbs to be clones by packing several MCTP packets into a single transfer (`mctp-usb.c:219`). No race, memory-layout dependency, or victim state is involved, and the kunit reproducer added by the fix triggers it deterministically.\nPR:N - There is no authentication or authorization anywhere on the path from `mctp_pkttype_receive()` to `mctp_frag_queue()` \u2014 MCTP packets are parsed and reassembled purely on header contents, so a device on the bus needs no credentials or local account.\nUI:N - Reassembly happens in softirq context on packet receive; no user action is needed on the victim system beyond having MCTP configured, which is the normal state for the affected BMC/host management deployments.\nS:U - The corruption and its consequences are confined to kernel skb structures within the same security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - Writing the reassembly `frag_list` into a shared `skb_shared_info` cross-links skbs belonging to different reassembly contexts and to other subsystems (e.g. AF_PACKET clones), so a socket can be delivered a fragment chain from an unrelated message with mismatched length accounting \u2014 memory-state corruption leveragable for disclosure of data from another context.\nI:H - The bug both delivers incorrectly reassembled message content to MCTP sockets (corrupting PLDM/NVMe-MI/NC-SI management traffic) and plants an attacker-influenced skb pointer into a `skb_shared_info` owned by other subsystems, which is later dereferenced and freed by an owner that never expected a fragment list.\nA:H - Every cloned fragmented message permanently leaks its skbs and backing data buffer through the circular `frag_list`/`dataref` reference, and the attacker can repeat this without limit \u2014 driving memory exhaustion and OOM/kernel failure on the memory-constrained BMC and embedded systems where MCTP is deployed."
            }
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      "providerMetadata": {
        "dateUpdated": "2026-08-05T11:55:47.567Z",
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        {
          "url": "https://git.kernel.org/stable/c/f5d83cf0eeb90fade4d5c4d17d24b8bee9ceeecc"
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      ],
      "title": "net: mctp: unshare packets when reassembling",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2025-21972",
    "datePublished": "2025-04-01T15:47:04.960Z",
    "dateReserved": "2024-12-29T08:45:45.797Z",
    "dateUpdated": "2026-08-05T11:55:47.567Z",
    "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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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.