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GHSA-MQ6P-2MW2-MP6G

Vulnerability from github – Published: 2026-10-18 18:31 – Updated: 2026-10-18 18:31

Details

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

bpf: Make post-verification instruction rewrites killable

After do_check() returns, the verifier runs several instruction rewrite passes. Some of them patch or remove one instruction at a time. Each operation moves the remaining instruction and auxiliary-data arrays and adjusts all branch offsets, making the overall work quadratic in the program length.

A privileged loader can submit 131072 unconditional jumps by zero followed by a valid return. Verification finishes quickly, but bpf_opt_remove_nops() then spends a long time removing each jump separately. Since this post-verification work neither checks for signals nor reschedules, a pending SIGKILL cannot terminate the task until the rewrite finishes.

Make bpf_patch_insn_data() and verifier_remove_insns() common cancellation and rescheduling points. These helpers run from BPF_PROG_LOAD process context, and bpf_patch_insn_data() can already sleep while reallocating auxiliary data.

Report interrupted constant blinding as -EINTR and propagate it through both JIT paths, including kernels that permit interpreter fallback. Other blinding failures retain the existing fallback behavior.

This does not reduce the quadratic cost of the rewrite passes, but it makes the work preemptible and allows a killed loader to be torn down promptly.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-98628"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-18T16:17:15Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Make post-verification instruction rewrites killable\n\nAfter do_check() returns, the verifier runs several instruction rewrite\npasses. Some of them patch or remove one instruction at a time. Each\noperation moves the remaining instruction and auxiliary-data arrays and\nadjusts all branch offsets, making the overall work quadratic in the\nprogram length.\n\nA privileged loader can submit 131072 unconditional jumps by zero followed\nby a valid return. Verification finishes quickly, but bpf_opt_remove_nops()\nthen spends a long time removing each jump separately. Since this\npost-verification work neither checks for signals nor reschedules, a pending\nSIGKILL cannot terminate the task until the rewrite finishes.\n\nMake bpf_patch_insn_data() and verifier_remove_insns() common cancellation\nand rescheduling points. These helpers run from BPF_PROG_LOAD process\ncontext, and bpf_patch_insn_data() can already sleep while reallocating\nauxiliary data.\n\nReport interrupted constant blinding as -EINTR and propagate it through\nboth JIT paths, including kernels that permit interpreter fallback.\nOther blinding failures retain the existing fallback behavior.\n\nThis does not reduce the quadratic cost of the rewrite passes, but it makes\nthe work preemptible and allows a killed loader to be torn down promptly.",
  "id": "GHSA-mq6p-2mw2-mp6g",
  "modified": "2026-10-18T18:31:57Z",
  "published": "2026-10-18T18:31:56Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98628"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/261b61d3735b042ae25634f795c4540be0fc140c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/56dc616d7a1f7d134d3e101c455e62b0a24d0cfd"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-98628 (GCVE-0-2026-98628)

Vulnerability from cvelistv5 – Published: 2026-10-18 15:19 – Updated: 2026-10-19 09:22

Title

bpf: Make post-verification instruction rewrites killable

Summary

In the Linux kernel, the following vulnerability has been resolved: bpf: Make post-verification instruction rewrites killable After do_check() returns, the verifier runs several instruction rewrite passes. Some of them patch or remove one instruction at a time. Each operation moves the remaining instruction and auxiliary-data arrays and adjusts all branch offsets, making the overall work quadratic in the program length. A privileged loader can submit 131072 unconditional jumps by zero followed by a valid return. Verification finishes quickly, but bpf_opt_remove_nops() then spends a long time removing each jump separately. Since this post-verification work neither checks for signals nor reschedules, a pending SIGKILL cannot terminate the task until the rewrite finishes. Make bpf_patch_insn_data() and verifier_remove_insns() common cancellation and rescheduling points. These helpers run from BPF_PROG_LOAD process context, and bpf_patch_insn_data() can already sleep while reallocating auxiliary data. Report interrupted constant blinding as -EINTR and propagate it through both JIT paths, including kernels that permit interpreter fallback. Other blinding failures retain the existing fallback behavior. This does not reduce the quadratic cost of the rewrite passes, but it makes the work preemptible and allows a killed loader to be torn down promptly.

Severity

No CVSS data available.

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 6820 records in the last 180 days details

References

2 references

URL	Tags
https://git.kernel.org/stable/c/56dc616d7a1f7d134…
https://git.kernel.org/stable/c/261b61d3735b042ae…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 52875a04f4b26e7ef30a288ea096f7cfec0e93cd , < 56dc616d7a1f7d134d3e101c455e62b0a24d0cfd (git) Affected: 52875a04f4b26e7ef30a288ea096f7cfec0e93cd , < 261b61d3735b042ae25634f795c4540be0fc140c (git)
Linux	Linux	Affected: 5.1 Unaffected: 0 , < 5.1 (semver) Unaffected: 7.2.9 , ≤ 7.2.* (semver) Unaffected: 7.3 , ≤ * (original_commit_for_fix)

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{
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        {
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          "programFiles": [
            "kernel/bpf/core.c",
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          ],
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          "vendor": "Linux",
          "versions": [
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              "lessThan": "56dc616d7a1f7d134d3e101c455e62b0a24d0cfd",
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              "version": "52875a04f4b26e7ef30a288ea096f7cfec0e93cd",
              "versionType": "git"
            },
            {
              "lessThan": "261b61d3735b042ae25634f795c4540be0fc140c",
              "status": "affected",
              "version": "52875a04f4b26e7ef30a288ea096f7cfec0e93cd",
              "versionType": "git"
            }
          ]
        },
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          "product": "Linux",
          "programFiles": [
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          ],
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          "vendor": "Linux",
          "versions": [
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            },
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              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
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              "cpeMatch": [
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                  "vulnerable": true
                },
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Make post-verification instruction rewrites killable\n\nAfter do_check() returns, the verifier runs several instruction rewrite\npasses. Some of them patch or remove one instruction at a time. Each\noperation moves the remaining instruction and auxiliary-data arrays and\nadjusts all branch offsets, making the overall work quadratic in the\nprogram length.\n\nA privileged loader can submit 131072 unconditional jumps by zero followed\nby a valid return. Verification finishes quickly, but bpf_opt_remove_nops()\nthen spends a long time removing each jump separately. Since this\npost-verification work neither checks for signals nor reschedules, a pending\nSIGKILL cannot terminate the task until the rewrite finishes.\n\nMake bpf_patch_insn_data() and verifier_remove_insns() common cancellation\nand rescheduling points. These helpers run from BPF_PROG_LOAD process\ncontext, and bpf_patch_insn_data() can already sleep while reallocating\nauxiliary data.\n\nReport interrupted constant blinding as -EINTR and propagate it through\nboth JIT paths, including kernels that permit interpreter fallback.\nOther blinding failures retain the existing fallback behavior.\n\nThis does not reduce the quadratic cost of the rewrite passes, but it makes\nthe work preemptible and allows a killed loader to be torn down promptly."
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        "dateUpdated": "2026-10-19T09:22:56.237Z",
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    "datePublished": "2026-10-18T15:19:49.746Z",
    "dateReserved": "2026-09-25T10:25:14.361Z",
    "dateUpdated": "2026-10-19T09:22:56.237Z",
    "state": "PUBLISHED"
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

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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.

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