Vulnerability-Lookup

GHSA-QHCG-6255-C538

Vulnerability from github – Published: 2026-06-25 09:31 – Updated: 2026-07-08 00:37

Details

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

rseq: Fix using an uninitialized stack variable in rseq_exit_user_update()

There is an bug in which an uninitialized stack variable is used in rseq_exit_user_update() as reported by syzbot:

BUG: KMSAN: kernel-infoleak in rseq_set_ids_get_csaddr include/linux/rseq_entry.h:502 [inline]

The local variable:

struct rseq_ids ids = {
    .cpu_id  = task_cpu(t),
    .mm_cid  = task_mm_cid(t),
    .node_id = cpu_to_node(ids.cpu_id),
};

According to the C standard, the evaluation order of expressions in an initializer list is indeterminately sequenced. The compiler (Clang, in this KMSAN build) evaluates cpu_to_node(ids.cpu_id) before ids.cpu_id is initialized with task_cpu(t).

This is fixed by moving the assignment of ids.node_id outside the structure initialization.

Severity

5.5 (Medium)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-53243"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-908"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-25T09:16:42Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nrseq: Fix using an uninitialized stack variable in rseq_exit_user_update()\n\nThere is an bug in which an uninitialized stack variable is used in\nrseq_exit_user_update() as reported by syzbot:\n\nBUG: KMSAN: kernel-infoleak in rseq_set_ids_get_csaddr include/linux/rseq_entry.h:502 [inline]\n\nThe local variable:\n\n\tstruct rseq_ids ids = {\n\t\t.cpu_id\t = task_cpu(t),\n\t\t.mm_cid\t = task_mm_cid(t),\n\t\t.node_id = cpu_to_node(ids.cpu_id),\n\t};\n\nAccording to the C standard, the evaluation order of expressions in an\ninitializer list is indeterminately sequenced. The compiler (Clang, in\nthis KMSAN build) evaluates `cpu_to_node(ids.cpu_id)` *before*\n`ids.cpu_id` is initialized with `task_cpu(t)`.\n\nThis is fixed by moving the assignment of ids.node_id outside the\nstructure initialization.",
  "id": "GHSA-qhcg-6255-c538",
  "modified": "2026-07-08T00:37:52Z",
  "published": "2026-06-25T09:31:22Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53243"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6d99479799c69c3cb588fcda19c81d8f61d64ecd"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e12d20a63b61aaf9de4772effccf42cc9a003e58"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-53243 (GCVE-0-2026-53243)

Vulnerability from cvelistv5 – Published: 2026-06-25 08:39 – Updated: 2026-06-25 08:39

Title

rseq: Fix using an uninitialized stack variable in rseq_exit_user_update()

Summary

In the Linux kernel, the following vulnerability has been resolved: rseq: Fix using an uninitialized stack variable in rseq_exit_user_update() There is an bug in which an uninitialized stack variable is used in rseq_exit_user_update() as reported by syzbot: BUG: KMSAN: kernel-infoleak in rseq_set_ids_get_csaddr include/linux/rseq_entry.h:502 [inline] The local variable: struct rseq_ids ids = { .cpu_id = task_cpu(t), .mm_cid = task_mm_cid(t), .node_id = cpu_to_node(ids.cpu_id), }; According to the C standard, the evaluation order of expressions in an initializer list is indeterminately sequenced. The compiler (Clang, in this KMSAN build) evaluates `cpu_to_node(ids.cpu_id)` *before* `ids.cpu_id` is initialized with `task_cpu(t)`. This is fixed by moving the assignment of ids.node_id outside the structure initialization.

Severity

No CVSS data available.

Assigner

Linux mitre root

References

2 references

URL	Tags
https://git.kernel.org/stable/c/e12d20a63b61aaf9d…
https://git.kernel.org/stable/c/6d99479799c69c3cb…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: d242126fd21ab8f1631fdbc8589e43a9d4229f3b , < e12d20a63b61aaf9de4772effccf42cc9a003e58 (git) Affected: 82f572449cfe75f12ea985986da60e11f308f77d , < 6d99479799c69c3cb588fcda19c81d8f61d64ecd (git)
Linux	Linux	Affected: 7.0.10 , < 7.0.13 (semver)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/linux/rseq_entry.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
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              "lessThan": "6d99479799c69c3cb588fcda19c81d8f61d64ecd",
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            }
          ]
        },
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "7.0.13",
              "status": "affected",
              "version": "7.0.10",
              "versionType": "semver"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.13",
                  "versionStartIncluding": "7.0.10",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
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        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrseq: Fix using an uninitialized stack variable in rseq_exit_user_update()\n\nThere is an bug in which an uninitialized stack variable is used in\nrseq_exit_user_update() as reported by syzbot:\n\nBUG: KMSAN: kernel-infoleak in rseq_set_ids_get_csaddr include/linux/rseq_entry.h:502 [inline]\n\nThe local variable:\n\n\tstruct rseq_ids ids = {\n\t\t.cpu_id\t = task_cpu(t),\n\t\t.mm_cid\t = task_mm_cid(t),\n\t\t.node_id = cpu_to_node(ids.cpu_id),\n\t};\n\nAccording to the C standard, the evaluation order of expressions in an\ninitializer list is indeterminately sequenced. The compiler (Clang, in\nthis KMSAN build) evaluates `cpu_to_node(ids.cpu_id)` *before*\n`ids.cpu_id` is initialized with `task_cpu(t)`.\n\nThis is fixed by moving the assignment of ids.node_id outside the\nstructure initialization."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-25T08:39:37.794Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/6d99479799c69c3cb588fcda19c81d8f61d64ecd"
        }
      ],
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    "datePublished": "2026-06-25T08:39:37.794Z",
    "dateReserved": "2026-06-09T07:44:35.393Z",
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    "state": "PUBLISHED"
  },
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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.

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

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