Vulnerability-Lookup

FKIE_CVE-2025-21836

Vulnerability from fkie_nvd - Published: 2025-03-07 09:15 - Updated: 2026-10-15 22:18

Severity

7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/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: io_uring/kbuf: reallocate buf lists on upgrade IORING_REGISTER_PBUF_RING can reuse an old struct io_buffer_list if it was created for legacy selected buffer and has been emptied. It violates the requirement that most of the field should stay stable after publish. Always reallocate it instead.

References

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/146a185f6c05ee263db715f860620606303c4633	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/2a5febbef40ce968e295a7aeaa5d5cbd9e3e5ad4	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/7d0dc28dae836caf7645fef62a10befc624dd17b	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/8802766324e1f5d414a81ac43365c20142e85603	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://u1f383.github.io/slides/talks/2025_Hexacon-Deja_Vu_in_Linux_io_uring_Breaking_Memory_Sharing_Again_After_Generations_of_Fixes.pdf

Impacted products

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

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "io_uring/kbuf.c"
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            },
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    },
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      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: io_uring/kbuf: reasignar listas de b\u00faferes en la actualizaci\u00f3n IORING_REGISTER_PBUF_RING puede reutilizar una estructura io_buffer_list antigua si se cre\u00f3 para un b\u00fafer seleccionado heredado y se vaci\u00f3. Viola el requisito de que la mayor parte del campo debe permanecer estable despu\u00e9s de la publicaci\u00f3n. Siempre reasignarlo en su lugar."
    }
  ],
  "id": "CVE-2025-21836",
  "lastModified": "2026-10-15T22:18:09.957",
  "metrics": {
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          "attackComplexity": "LOW",
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          "baseSeverity": "HIGH",
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        "type": "Secondary"
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          "userInteraction": "NONE",
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          "options": [
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          "timestamp": "2026-10-15T21:43:15.462435Z",
          "version": "2.0.3"
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  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Modified",
  "weaknesses": [
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}

CVE-2025-21836 (GCVE-0-2025-21836)

Vulnerability from cvelistv5 – Published: 2025-03-07 09:09 – Updated: 2026-10-15 21:51

Title

io_uring/kbuf: reallocate buf lists on upgrade

Summary

Severity

7.8 (High)


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

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-15 21:43 UTC

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 6637 records in the last 180 days details

References

5 references

URL	Tags
https://git.kernel.org/stable/c/146a185f6c05ee263…
https://git.kernel.org/stable/c/7d0dc28dae836caf7…
https://git.kernel.org/stable/c/2a5febbef40ce968e…
https://git.kernel.org/stable/c/8802766324e1f5d41…
https://u1f383.github.io/slides/talks/2025_Hexaco…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 2fcabce2d7d34f69a888146dab15b36a917f09d4 , < 146a185f6c05ee263db715f860620606303c4633 (git) Affected: 2fcabce2d7d34f69a888146dab15b36a917f09d4 , < 7d0dc28dae836caf7645fef62a10befc624dd17b (git) Affected: 2fcabce2d7d34f69a888146dab15b36a917f09d4 , < 2a5febbef40ce968e295a7aeaa5d5cbd9e3e5ad4 (git) Affected: 2fcabce2d7d34f69a888146dab15b36a917f09d4 , < 8802766324e1f5d414a81ac43365c20142e85603 (git)
Linux	Linux	Affected: 5.19 Unaffected: 0 , < 5.19 (semver) Unaffected: 6.6.79 , ≤ 6.6.* (semver) Unaffected: 6.12.16 , ≤ 6.12.* (semver) Unaffected: 6.13.4 , ≤ 6.13.* (semver) Unaffected: 6.14 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2025-21836",
                "options": [
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                  },
                  {
                    "Technical Impact": "total"
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                "role": "CISA Coordinator",
                "timestamp": "2026-10-15T21:43:15.462435Z",
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          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
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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.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

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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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