FKIE_CVE-2026-98034

Vulnerability from fkie_nvd - Published: 2026-09-25 11:17 - Updated: 2026-09-25 11:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Mark NULL kptr stores precise check_map_kptr_access() permits a scalar store into an untrusted kptr field only when the register is known to contain zero. Unlike other verifier checks whose outcome depends on a scalar value, it does not mark that register precise. A state checkpoint reached with an imprecise zero can therefore prune a second path that reaches the store with an arbitrary nonzero scalar. The program can write attacker-controlled bits into the kptr field and load them back as a PTR_TO_BTF_ID. Call mark_chain_precision() before accepting a known-zero register. This forces state equivalence to compare its scalar range and makes the verifier visit and reject a path carrying a nonzero value.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/86168208737bdd267d92d855d453d1d2f840df19
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ecdc5043794c9184aa8e6c814603899479c46b35
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/bpf/verifier.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "86168208737bdd267d92d855d453d1d2f840df19",
              "status": "affected",
              "version": "61df10c7799e27807ad5e459eec9d77cddf8bf45",
              "versionType": "git"
            },
            {
              "lessThan": "ecdc5043794c9184aa8e6c814603899479c46b35",
              "status": "affected",
              "version": "61df10c7799e27807ad5e459eec9d77cddf8bf45",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "b5a8069835e5236824a84281592d29f859b33153",
              "versionType": "git"
            },
            {
              "lessThan": "5.19",
              "status": "affected",
              "version": "5.18.18",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/bpf/verifier.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.19"
            },
            {
              "lessThan": "5.19",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Mark NULL kptr stores precise\n\ncheck_map_kptr_access() permits a scalar store into an untrusted kptr\nfield only when the register is known to contain zero. Unlike other\nverifier checks whose outcome depends on a scalar value, it does not mark\nthat register precise.\n\nA state checkpoint reached with an imprecise zero can therefore prune a\nsecond path that reaches the store with an arbitrary nonzero scalar. The\nprogram can write attacker-controlled bits into the kptr field and load\nthem back as a PTR_TO_BTF_ID.\n\nCall mark_chain_precision() before accepting a known-zero register. This\nforces state equivalence to compare its scalar range and makes the verifier\nvisit and reject a path carrying a nonzero value."
    }
  ],
  "id": "CVE-2026-98034",
  "lastModified": "2026-09-25T11:17:32.123",
  "metrics": {},
  "published": "2026-09-25T11:17:32.123",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/86168208737bdd267d92d855d453d1d2f840df19"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ecdc5043794c9184aa8e6c814603899479c46b35"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





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.



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.