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GHSA-FH67-PC46-97CW

Vulnerability from github – Published: 2026-09-24 18:31 – Updated: 2026-09-24 18:31

Details

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

arm64: entry: Avoid unnecessary local_irq_disable() on kernel exit

Currently, when exiting to kernel mode, we attempt involuntary preemption. The preemption logic expects IRQs to be disabled, which is why we call local_irq_disable() before attempting preemption.

However, depending on the context, local_irq_disable() may be unnecessary:

__el1_irq(), the non-NMI EL1 IRQ path, already has IRQs disabled, so local_irq_disable() is redundant.
irqentry_exit_to_kernel_mode_preempt() immediately returns when exiting from an NMI-like context, so calling local_irq_disable() beforehand is unnecessary work.

Furthermore, it confuses the pNMI state tracking when we are in a context with interrupts disabled and the GIC_PRIO_PSR_I_SET bit is set in the PMR, leading to a warning when CONFIG_ARM64_DEBUG_PRIORITY_MASKING=y:

 WARNING: ./arch/arm64/include/asm/irqflags.h:63 at arm64_exit_to_kernel_mode+0xb8/0xc0, CPU#40: retsnoop/31805
 CPU: 40 UID: 0 PID: 31805 Comm: retsnoop Not tainted 7.2.0-rc6-next-20260805 #7 PREEMPTLAZY
 pstate: 234013c9 (nzCv DAIF +PAN -UAO +TCO +DIT +SSBS BTYPE=--)
 pc : arm64_exit_to_kernel_mode (arch/arm64/kernel/entry-common.c:63)
 lr : el1_abort (arch/arm64/kernel/entry-common.c:323)
 pmr: 000000f0
 Call trace:
  arm64_exit_to_kernel_mode (arch/arm64/kernel/entry-common.c:63) (P)
  el1_abort (arch/arm64/kernel/entry-common.c:323)
  el1h_64_sync_handler (arch/arm64/kernel/entry-common.c:449)
  el1h_64_sync (arch/arm64/kernel/entry.S:589)
  [...]

Split arm64_exit_to_kernel_mode() into preempt, non-preempt, and dispatch parts so that we can avoid this extra work where it is not needed and avoid breaking the pNMI tracking logic.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-93254"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-24T16:17:21Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\narm64: entry: Avoid unnecessary local_irq_disable() on kernel exit\n\nCurrently, when exiting to kernel mode, we attempt involuntary\npreemption. The preemption logic expects IRQs to be disabled, which is\nwhy we call local_irq_disable() before attempting preemption.\n\nHowever, depending on the context, local_irq_disable() may be\nunnecessary:\n\n- __el1_irq(), the non-NMI EL1 IRQ path, already has IRQs disabled, so\n  local_irq_disable() is redundant.\n\n- irqentry_exit_to_kernel_mode_preempt() immediately returns when\n  exiting from an NMI-like context, so calling local_irq_disable()\n  beforehand is unnecessary work.\n\nFurthermore, it confuses the pNMI state tracking when we are in a\ncontext with interrupts disabled and the GIC_PRIO_PSR_I_SET bit is set\nin the PMR, leading to a warning when\nCONFIG_ARM64_DEBUG_PRIORITY_MASKING=y:\n\n     WARNING: ./arch/arm64/include/asm/irqflags.h:63 at arm64_exit_to_kernel_mode+0xb8/0xc0, CPU#40: retsnoop/31805\n     CPU: 40 UID: 0 PID: 31805 Comm: retsnoop Not tainted 7.2.0-rc6-next-20260805 #7 PREEMPTLAZY\n     pstate: 234013c9 (nzCv DAIF +PAN -UAO +TCO +DIT +SSBS BTYPE=--)\n     pc : arm64_exit_to_kernel_mode (arch/arm64/kernel/entry-common.c:63)\n     lr : el1_abort (arch/arm64/kernel/entry-common.c:323)\n     pmr: 000000f0\n     Call trace:\n      arm64_exit_to_kernel_mode (arch/arm64/kernel/entry-common.c:63) (P)\n      el1_abort (arch/arm64/kernel/entry-common.c:323)\n      el1h_64_sync_handler (arch/arm64/kernel/entry-common.c:449)\n      el1h_64_sync (arch/arm64/kernel/entry.S:589)\n      [...]\n\nSplit arm64_exit_to_kernel_mode() into preempt, non-preempt, and\ndispatch parts so that we can avoid this extra work where it is not\nneeded and avoid breaking the pNMI tracking logic.",
  "id": "GHSA-fh67-pc46-97cw",
  "modified": "2026-09-24T18:31:24Z",
  "published": "2026-09-24T18:31:24Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-93254"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/39aebe0e89469c2904e60b1e977e0d4dbf33326b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/49a61174186bed25d439ff37400c7ce5e3603e73"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-93254 (GCVE-0-2026-93254)

Vulnerability from cvelistv5 – Published: 2026-09-24 15:51 – Updated: 2026-09-24 15:51

Title

arm64: entry: Avoid unnecessary local_irq_disable() on kernel exit

Summary

In the Linux kernel, the following vulnerability has been resolved: arm64: entry: Avoid unnecessary local_irq_disable() on kernel exit Currently, when exiting to kernel mode, we attempt involuntary preemption. The preemption logic expects IRQs to be disabled, which is why we call local_irq_disable() before attempting preemption. However, depending on the context, local_irq_disable() may be unnecessary: - __el1_irq(), the non-NMI EL1 IRQ path, already has IRQs disabled, so local_irq_disable() is redundant. - irqentry_exit_to_kernel_mode_preempt() immediately returns when exiting from an NMI-like context, so calling local_irq_disable() beforehand is unnecessary work. Furthermore, it confuses the pNMI state tracking when we are in a context with interrupts disabled and the GIC_PRIO_PSR_I_SET bit is set in the PMR, leading to a warning when CONFIG_ARM64_DEBUG_PRIORITY_MASKING=y: WARNING: ./arch/arm64/include/asm/irqflags.h:63 at arm64_exit_to_kernel_mode+0xb8/0xc0, CPU#40: retsnoop/31805 CPU: 40 UID: 0 PID: 31805 Comm: retsnoop Not tainted 7.2.0-rc6-next-20260805 #7 PREEMPTLAZY pstate: 234013c9 (nzCv DAIF +PAN -UAO +TCO +DIT +SSBS BTYPE=--) pc : arm64_exit_to_kernel_mode (arch/arm64/kernel/entry-common.c:63) lr : el1_abort (arch/arm64/kernel/entry-common.c:323) pmr: 000000f0 Call trace: arm64_exit_to_kernel_mode (arch/arm64/kernel/entry-common.c:63) (P) el1_abort (arch/arm64/kernel/entry-common.c:323) el1h_64_sync_handler (arch/arm64/kernel/entry-common.c:449) el1h_64_sync (arch/arm64/kernel/entry.S:589) [...] Split arm64_exit_to_kernel_mode() into preempt, non-preempt, and dispatch parts so that we can avoid this extra work where it is not needed and avoid breaking the pNMI tracking logic.

Severity

No CVSS data available.

Assigner

Linux mitre root

References

2 references

URL	Tags
https://git.kernel.org/stable/c/49a61174186bed25d…
https://git.kernel.org/stable/c/39aebe0e89469c290…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: ae654112eac05f316ef31587fc55e4d7160d0086 , < 49a61174186bed25d439ff37400c7ce5e3603e73 (git) Affected: ae654112eac05f316ef31587fc55e4d7160d0086 , < 39aebe0e89469c2904e60b1e977e0d4dbf33326b (git)
Linux	Linux	Affected: 7.1 Unaffected: 0 , < 7.1 (semver) Unaffected: 7.2.6 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)

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JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/arm64/kernel/entry-common.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "49a61174186bed25d439ff37400c7ce5e3603e73",
              "status": "affected",
              "version": "ae654112eac05f316ef31587fc55e4d7160d0086",
              "versionType": "git"
            },
            {
              "lessThan": "39aebe0e89469c2904e60b1e977e0d4dbf33326b",
              "status": "affected",
              "version": "ae654112eac05f316ef31587fc55e4d7160d0086",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/arm64/kernel/entry-common.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.1"
            },
            {
              "lessThan": "7.1",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "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": "7.2.6",
                  "versionStartIncluding": "7.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "7.1",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\narm64: entry: Avoid unnecessary local_irq_disable() on kernel exit\n\nCurrently, when exiting to kernel mode, we attempt involuntary\npreemption. The preemption logic expects IRQs to be disabled, which is\nwhy we call local_irq_disable() before attempting preemption.\n\nHowever, depending on the context, local_irq_disable() may be\nunnecessary:\n\n- __el1_irq(), the non-NMI EL1 IRQ path, already has IRQs disabled, so\n  local_irq_disable() is redundant.\n\n- irqentry_exit_to_kernel_mode_preempt() immediately returns when\n  exiting from an NMI-like context, so calling local_irq_disable()\n  beforehand is unnecessary work.\n\nFurthermore, it confuses the pNMI state tracking when we are in a\ncontext with interrupts disabled and the GIC_PRIO_PSR_I_SET bit is set\nin the PMR, leading to a warning when\nCONFIG_ARM64_DEBUG_PRIORITY_MASKING=y:\n\n     WARNING: ./arch/arm64/include/asm/irqflags.h:63 at arm64_exit_to_kernel_mode+0xb8/0xc0, CPU#40: retsnoop/31805\n     CPU: 40 UID: 0 PID: 31805 Comm: retsnoop Not tainted 7.2.0-rc6-next-20260805 #7 PREEMPTLAZY\n     pstate: 234013c9 (nzCv DAIF +PAN -UAO +TCO +DIT +SSBS BTYPE=--)\n     pc : arm64_exit_to_kernel_mode (arch/arm64/kernel/entry-common.c:63)\n     lr : el1_abort (arch/arm64/kernel/entry-common.c:323)\n     pmr: 000000f0\n     Call trace:\n      arm64_exit_to_kernel_mode (arch/arm64/kernel/entry-common.c:63) (P)\n      el1_abort (arch/arm64/kernel/entry-common.c:323)\n      el1h_64_sync_handler (arch/arm64/kernel/entry-common.c:449)\n      el1h_64_sync (arch/arm64/kernel/entry.S:589)\n      [...]\n\nSplit arm64_exit_to_kernel_mode() into preempt, non-preempt, and\ndispatch parts so that we can avoid this extra work where it is not\nneeded and avoid breaking the pNMI tracking logic."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-24T15:51:40.955Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/49a61174186bed25d439ff37400c7ce5e3603e73"
        },
        {
          "url": "https://git.kernel.org/stable/c/39aebe0e89469c2904e60b1e977e0d4dbf33326b"
        }
      ],
      "title": "arm64: entry: Avoid unnecessary local_irq_disable() on kernel exit",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-93254",
    "datePublished": "2026-09-24T15:51:40.955Z",
    "dateReserved": "2026-09-17T16:02:15.096Z",
    "dateUpdated": "2026-09-24T15:51:40.955Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

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Nomenclature

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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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GHSA-FH67-PC46-97CW

CVE-2026-93254 (GCVE-0-2026-93254)

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