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GHSA-MQMH-F84H-6J7H

Vulnerability from github – Published: 2026-09-11 21:31 – Updated: 2026-09-13 09:32

Details

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

s390/percpu: Fix MVIY_PERCPU() with older binutils

Commit a737737cdb9c ("s390/percpu: Infrastructure for more efficient this_cpu operations") introduced MVIY_PERCPU(), which stringifies arguments that are already C string literals. This generates an assembler macro invocation with whitespace-separated quoted arguments:

GEN_MVIY "459712" "%r3"

GNU as versions prior to binutils 2.39 drop the separating whitespace between quoted macro arguments during input scrubbing. They consequently parse the invocation as a single argument and emit repeated warnings:

Warning: missing closing `"'

The .ifc in GEN_MVIY never matches and GNU as exits successfully without emitting the mviy instruction. As a result, the interrupted per-CPU sequence is not marked in lowcore and the exception return path cannot repair the per-CPU address register after migration.

All MVIY_PERCPU() callers pass C string literals. Use them directly and separate the assembler macro arguments with an explicit comma. The resulting invocation is:

GEN_MVIY 459712, %r3

This form is unambiguous for GNU as and LLVM's integrated assembler. This behavior was fixed in GNU as from binutils 2.39, but Linux supports binutils 2.30.

Severity

7.0 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-89459"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-11T20:19:26Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/percpu: Fix MVIY_PERCPU() with older binutils\n\nCommit a737737cdb9c (\"s390/percpu: Infrastructure for more efficient\nthis_cpu operations\") introduced MVIY_PERCPU(), which stringifies\narguments that are already C string literals. This generates an\nassembler macro invocation with whitespace-separated quoted arguments:\n\n  GEN_MVIY \"459712\" \"%r3\"\n\nGNU as versions prior to binutils 2.39 drop the separating whitespace\nbetween quoted macro arguments during input scrubbing. They\nconsequently parse the invocation as a single argument and emit\nrepeated warnings:\n\n  Warning: missing closing `\"\u0027\n\nThe .ifc in GEN_MVIY never matches and GNU as exits successfully\nwithout emitting the mviy instruction. As a result, the interrupted\nper-CPU sequence is not marked in lowcore and the exception return\npath cannot repair the per-CPU address register after migration.\n\nAll MVIY_PERCPU() callers pass C string literals. Use them directly\nand separate the assembler macro arguments with an explicit comma. The\nresulting invocation is:\n\n  GEN_MVIY 459712, %r3\n\nThis form is unambiguous for GNU as and LLVM\u0027s integrated assembler.\nThis behavior was fixed in GNU as from binutils 2.39, but Linux\nsupports binutils 2.30.",
  "id": "GHSA-mqmh-f84h-6j7h",
  "modified": "2026-09-13T09:32:12Z",
  "published": "2026-09-11T21:31:27Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89459"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/101782f8945a125044347312d74d488c05741c4a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/91770b08a120967077ae78600612f18bc5ee3caf"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-89459 (GCVE-0-2026-89459)

Vulnerability from cvelistv5 – Published: 2026-09-11 19:43 – Updated: 2026-09-13 06:29

Title

s390/percpu: Fix MVIY_PERCPU() with older binutils

Summary

In the Linux kernel, the following vulnerability has been resolved: s390/percpu: Fix MVIY_PERCPU() with older binutils Commit a737737cdb9c ("s390/percpu: Infrastructure for more efficient this_cpu operations") introduced MVIY_PERCPU(), which stringifies arguments that are already C string literals. This generates an assembler macro invocation with whitespace-separated quoted arguments: GEN_MVIY "459712" "%r3" GNU as versions prior to binutils 2.39 drop the separating whitespace between quoted macro arguments during input scrubbing. They consequently parse the invocation as a single argument and emit repeated warnings: Warning: missing closing `"' The .ifc in GEN_MVIY never matches and GNU as exits successfully without emitting the mviy instruction. As a result, the interrupted per-CPU sequence is not marked in lowcore and the exception return path cannot repair the per-CPU address register after migration. All MVIY_PERCPU() callers pass C string literals. Use them directly and separate the assembler macro arguments with an explicit comma. The resulting invocation is: GEN_MVIY 459712, %r3 This form is unambiguous for GNU as and LLVM's integrated assembler. This behavior was fixed in GNU as from binutils 2.39, but Linux supports binutils 2.30.

Severity

7 (High)


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

Assigner

Linux mitre root

References

2 references

URL	Tags
https://git.kernel.org/stable/c/91770b08a12096707…
https://git.kernel.org/stable/c/101782f8945a12504…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: a737737cdb9c94e40a9926cdc2320f874c05d709 , < 91770b08a120967077ae78600612f18bc5ee3caf (git) Affected: a737737cdb9c94e40a9926cdc2320f874c05d709 , < 101782f8945a125044347312d74d488c05741c4a (git)
Linux	Linux	Affected: 7.2 Unaffected: 0 , < 7.2 (semver) Unaffected: 7.2.4 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/s390/include/asm/percpu.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "91770b08a120967077ae78600612f18bc5ee3caf",
              "status": "affected",
              "version": "a737737cdb9c94e40a9926cdc2320f874c05d709",
              "versionType": "git"
            },
            {
              "lessThan": "101782f8945a125044347312d74d488c05741c4a",
              "status": "affected",
              "version": "a737737cdb9c94e40a9926cdc2320f874c05d709",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/s390/include/asm/percpu.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.2"
            },
            {
              "lessThan": "7.2",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.4",
                  "versionStartIncluding": "7.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "7.2",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/percpu: Fix MVIY_PERCPU() with older binutils\n\nCommit a737737cdb9c (\"s390/percpu: Infrastructure for more efficient\nthis_cpu operations\") introduced MVIY_PERCPU(), which stringifies\narguments that are already C string literals. This generates an\nassembler macro invocation with whitespace-separated quoted arguments:\n\n  GEN_MVIY \"459712\" \"%r3\"\n\nGNU as versions prior to binutils 2.39 drop the separating whitespace\nbetween quoted macro arguments during input scrubbing. They\nconsequently parse the invocation as a single argument and emit\nrepeated warnings:\n\n  Warning: missing closing `\"\u0027\n\nThe .ifc in GEN_MVIY never matches and GNU as exits successfully\nwithout emitting the mviy instruction. As a result, the interrupted\nper-CPU sequence is not marked in lowcore and the exception return\npath cannot repair the per-CPU address register after migration.\n\nAll MVIY_PERCPU() callers pass C string literals. Use them directly\nand separate the assembler macro arguments with an explicit comma. The\nresulting invocation is:\n\n  GEN_MVIY 459712, %r3\n\nThis form is unambiguous for GNU as and LLVM\u0027s integrated assembler.\nThis behavior was fixed in GNU as from binutils 2.39, but Linux\nsupports binutils 2.30."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The omitted mviy start marker is in s390 this_cpu_read/write/add sequences reached from local syscalls (mm/swap, memcg, vmalloc) and user-namespace nftables; this is an arch per-CPU primitive, not a packet parser, ksmbd/nfsd handler, or USB path.\nAC:H - The op is wrong only if an interrupt or preemption and a CPU migration both occur after AG adds the old CPU offset and before the atomic instruction; that one-instruction window is not attacker-timed, even with affinity bouncing on default PREEMPT_LAZY s390.\nPR:L - Any unprivileged local user can drive this_cpu_* via ordinary syscalls, and nft_ct\u0027s this_cpu_read(nft_ct_pcpu_template) is reachable with CAP_NET_ADMIN in a user namespace; init-namespace root is not required.\nUI:N - The attacker triggers the unmarked this_cpu sequences from their own process (syscalls or locally generated packets); no victim mount, file open, or other interaction is required.\nS:U - Stale per-CPU pointers are used inside the same host kernel after migration; this is not a KVM/Xen guest-to-host escape or IOMMU/DMA boundary bypass.\nC:H - After migration, this_cpu_read uses another CPU\u0027s pointer-typed slots (percpu_swap_cluster.si, nft_ct_pcpu_template, page-pool/socket pointers) without that CPU\u0027s locking, which can disclose kernel objects and is memory corruption leverageable for info disclosure.\nI:H - The matching this_cpu_write/add then mutates the previous CPU\u0027s per-CPU state (swap cluster cache, conntrack templates, other CPU-local structures that assume exclusive access), which is kernel memory corruption exploitable toward control-flow hijack.\nA:H - A stale per-CPU pointer after migration can oops or panic (NULL vmalloc ne_fit_preload_node, inconsistent swap_info, conntrack refcount UAF), which is a full kernel availability loss on SMP s390."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-13T06:29:33.766Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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      "references": [
        {
          "url": "https://git.kernel.org/stable/c/91770b08a120967077ae78600612f18bc5ee3caf"
        },
        {
          "url": "https://git.kernel.org/stable/c/101782f8945a125044347312d74d488c05741c4a"
        }
      ],
      "title": "s390/percpu: Fix MVIY_PERCPU() with older binutils",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89459",
    "datePublished": "2026-09-11T19:43:22.007Z",
    "dateReserved": "2026-09-11T19:38:34.707Z",
    "dateUpdated": "2026-09-13T06:29:33.766Z",
    "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.

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.
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GHSA-MQMH-F84H-6J7H

CVE-2026-89459 (GCVE-0-2026-89459)

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