CVE-2026-98888

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: arm64: kprobes: Allow reentering kprobes while single-stepping A kprobe can be hit while another kprobe is in KPROBE_HIT_SS state. This can happen when tracing or perf code runs from the debug exception path while the first kprobe is preparing or executing its out-of-line single-step instruction. Currently arm64 treats a kprobe hit in KPROBE_HIT_SS as unrecoverable, the same as a hit in KPROBE_REENTER. This is too strict. A hit in KPROBE_HIT_SS is still a one-level reentry and can be handled by saving the current kprobe state and setting up single-step for the new probe, just like reentry from KPROBE_HIT_ACTIVE or KPROBE_HIT_SSDONE. The truly unrecoverable case is hitting another kprobe while already in KPROBE_REENTER, because the reentry save area has already been consumed. Move KPROBE_HIT_SS to the recoverable reentry cases and leave KPROBE_REENTER as the unrecoverable nested reentry case. This change also requires saving saved_irqflag in struct prev_kprobe. When a nested kprobe calls kprobes_save_local_irqflag(), it overwrites kcb->saved_irqflag with the currently masked DAIF value, losing the outer kprobe's original DAIF state. Without this fix, when the outer kprobe's single-step finishes, kprobes_restore_local_irqflag() applies the wrong DAIF mask and leaves interrupts permanently disabled. Extend struct prev_kprobe with a saved_irqflag field and save/restore it alongside kp and status. This ensures the outer kprobe's original interrupt state is preserved across reentry. This mirrors the x86 fix in commit 6a5022a56ac3 ("kprobes/x86: Allow to handle reentered kprobe on single-stepping").

Severity

Not scored

CVSS score

Not available

Vulnerability status

Received

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-10-23 12:18:22.583000

Last modified

2026-10-26 07:17:13.870000

View original CVE JSON

{
  "id": "CVE-2026-98888",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-10-23T12:18:22.583",
  "lastModified": "2026-10-26T07:17:13.870",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\narm64: kprobes: Allow reentering kprobes while single-stepping\n\nA kprobe can be hit while another kprobe is in KPROBE_HIT_SS state. This\ncan happen when tracing or perf code runs from the debug exception path\nwhile the first kprobe is preparing or executing its out-of-line\nsingle-step instruction.\n\nCurrently arm64 treats a kprobe hit in KPROBE_HIT_SS as unrecoverable,\nthe same as a hit in KPROBE_REENTER. This is too strict. A hit in\nKPROBE_HIT_SS is still a one-level reentry and can be handled by saving\nthe current kprobe state and setting up single-step for the new probe,\njust like reentry from KPROBE_HIT_ACTIVE or KPROBE_HIT_SSDONE.\n\nThe truly unrecoverable case is hitting another kprobe while already in\nKPROBE_REENTER, because the reentry save area has already been consumed.\n\nMove KPROBE_HIT_SS to the recoverable reentry cases and leave\nKPROBE_REENTER as the unrecoverable nested reentry case.\n\nThis change also requires saving saved_irqflag in struct prev_kprobe.\nWhen a nested kprobe calls kprobes_save_local_irqflag(), it overwrites\nkcb->saved_irqflag with the currently masked DAIF value, losing the\nouter kprobe's original DAIF state. Without this fix, when the outer\nkprobe's single-step finishes, kprobes_restore_local_irqflag() applies\nthe wrong DAIF mask and leaves interrupts permanently disabled.\n\nExtend struct prev_kprobe with a saved_irqflag field and save/restore it\nalongside kp and status. This ensures the outer kprobe's original\ninterrupt state is preserved across reentry.\n\nThis mirrors the x86 fix in commit 6a5022a56ac3\n(\"kprobes/x86: Allow to handle reentered kprobe on single-stepping\")."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "arch/arm64/include/asm/kprobes.h",
            "arch/arm64/kernel/probes/kprobes.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "2dd0e8d2d2a157dbc83295a78336c2217110f2f8",
              "lessThan": "bb0fe9121aa0824211aafa33c7d0151fd25ddb75",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "2dd0e8d2d2a157dbc83295a78336c2217110f2f8",
              "lessThan": "f96a0606de6bcc8d937b80e6470fd7a174c17e26",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "2dd0e8d2d2a157dbc83295a78336c2217110f2f8",
              "lessThan": "1f342b3e44c3035a837b53b217d816f7511c0d0a",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "2dd0e8d2d2a157dbc83295a78336c2217110f2f8",
              "lessThan": "c8e84e292ed4cfc199824146da71bb4397b02a1f",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "2dd0e8d2d2a157dbc83295a78336c2217110f2f8",
              "lessThan": "68774caca799e9695db56d426c69acebd041c2ed",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "2dd0e8d2d2a157dbc83295a78336c2217110f2f8",
              "lessThan": "a21bf9cb893126e8d9730995708d0be5eb167652",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "2dd0e8d2d2a157dbc83295a78336c2217110f2f8",
              "lessThan": "23f851ac0078a908bf3422d6467ebc1db5828c46",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "arch/arm64/include/asm/kprobes.h",
            "arch/arm64/kernel/probes/kprobes.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "4.8",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "4.8",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "5.10.271",
              "lessThanOrEqual": "5.10.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "5.15.222",
              "lessThanOrEqual": "5.15.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.1.189",
              "lessThanOrEqual": "6.1.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.6.158",
              "lessThanOrEqual": "6.6.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.12.111",
              "lessThanOrEqual": "6.12.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.53",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/1f342b3e44c3035a837b53b217d816f7511c0d0a",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/23f851ac0078a908bf3422d6467ebc1db5828c46",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/68774caca799e9695db56d426c69acebd041c2ed",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a21bf9cb893126e8d9730995708d0be5eb167652",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/bb0fe9121aa0824211aafa33c7d0151fd25ddb75",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/c8e84e292ed4cfc199824146da71bb4397b02a1f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f96a0606de6bcc8d937b80e6470fd7a174c17e26",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}