CVE-2026-98888 (GCVE-0-2026-98888)

Vulnerability from cvelistv5 – Published: 2026-10-23 11:37 – Updated: 2026-10-23 11:37
VLAI
Title
arm64: kprobes: Allow reentering kprobes while single-stepping
Summary
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
No CVSS data available.
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 7056 records in the last 180 days details
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < bb0fe9121aa0824211aafa33c7d0151fd25ddb75 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < f96a0606de6bcc8d937b80e6470fd7a174c17e26 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 1f342b3e44c3035a837b53b217d816f7511c0d0a (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < c8e84e292ed4cfc199824146da71bb4397b02a1f (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 68774caca799e9695db56d426c69acebd041c2ed (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < a21bf9cb893126e8d9730995708d0be5eb167652 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 23f851ac0078a908bf3422d6467ebc1db5828c46 (git)
Affected: 0 , < 5.10.271 (semver)
Affected: 0 , < 5.15.222 (semver)
Affected: 0 , < 6.1.189 (semver)
Affected: 0 , < 6.6.158 (semver)
Affected: 0 , < 6.12.111 (semver)
Affected: 0 , < 6.18.53 (semver)
guessed Create a notification for this product.
Linux Linux Unaffected: 5.10.271 , ≤ 5.10.* (semver)
Unaffected: 5.15.222 , ≤ 5.15.* (semver)
Unaffected: 6.1.189 , ≤ 6.1.* (semver)
Unaffected: 6.6.158 , ≤ 6.6.* (semver)
Unaffected: 6.12.111 , ≤ 6.12.* (semver)
Unaffected: 6.18.53 , ≤ 6.18.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website

{
  "containers": {
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          "product": "Linux",
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            "arch/arm64/include/asm/kprobes.h",
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            "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",
          "vendor": "Linux",
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              "status": "unaffected",
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              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
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          "nodes": [
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              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionEndExcluding": "5.15.222",
                  "vulnerable": true
                },
                {
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                  "versionEndExcluding": "6.1.189",
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                {
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              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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-\u003esaved_irqflag with the currently masked DAIF value, losing the\nouter kprobe\u0027s original DAIF state. Without this fix, when the outer\nkprobe\u0027s 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\u0027s 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\")."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-23T11:37:46.984Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/bb0fe9121aa0824211aafa33c7d0151fd25ddb75"
        },
        {
          "url": "https://git.kernel.org/stable/c/f96a0606de6bcc8d937b80e6470fd7a174c17e26"
        },
        {
          "url": "https://git.kernel.org/stable/c/1f342b3e44c3035a837b53b217d816f7511c0d0a"
        },
        {
          "url": "https://git.kernel.org/stable/c/c8e84e292ed4cfc199824146da71bb4397b02a1f"
        },
        {
          "url": "https://git.kernel.org/stable/c/68774caca799e9695db56d426c69acebd041c2ed"
        },
        {
          "url": "https://git.kernel.org/stable/c/a21bf9cb893126e8d9730995708d0be5eb167652"
        },
        {
          "url": "https://git.kernel.org/stable/c/23f851ac0078a908bf3422d6467ebc1db5828c46"
        }
      ],
      "title": "arm64: kprobes: Allow reentering kprobes while single-stepping",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98888",
    "datePublished": "2026-10-23T11:37:46.984Z",
    "dateReserved": "2026-09-25T10:25:14.378Z",
    "dateUpdated": "2026-10-23T11:37:46.984Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-98888",
      "date": "2026-10-24",
      "epss": "0.00215",
      "percentile": "0.11286"
    },
    "microsoft_vex": {
      "current_release_date": "2026-10-24T01:05:18.000Z",
      "cve": "CVE-2026-98888",
      "id": "msrc_CVE-2026-98888",
      "initial_release_date": "2026-10-24T01:04:09.000Z",
      "product_status:known_affected": "1",
      "product_status:under_investigation": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "arm64: kprobes: Allow reentering kprobes while single-stepping",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-98888.json",
      "version": "2"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "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",
                "vendor": "Linux",
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                  {
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                    "versionType": "git"
                  },
                  {
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                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
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            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "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-\u003esaved_irqflag with the currently masked DAIF value, losing the\nouter kprobe\u0027s original DAIF state. Without this fix, when the outer\nkprobe\u0027s 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\u0027s 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\")."
          }
        ],
        "id": "CVE-2026-98888",
        "lastModified": "2026-10-23T12:18:22.583",
        "metrics": {},
        "published": "2026-10-23T12:18:22.583",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "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"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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

JSON
Events included in the timeline

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    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.