CVE-2026-31430 (GCVE-0-2026-31430)

Vulnerability from cvelistv5 – Published: 2026-04-20 09:43 – Updated: 2026-04-20 09:43
VLAI?
Title
X.509: Fix out-of-bounds access when parsing extensions
Summary
In the Linux kernel, the following vulnerability has been resolved: X.509: Fix out-of-bounds access when parsing extensions Leo reports an out-of-bounds access when parsing a certificate with empty Basic Constraints or Key Usage extension because the first byte of the extension is read before checking its length. Fix it. The bug can be triggered by an unprivileged user by submitting a specially crafted certificate to the kernel through the keyrings(7) API. Leo has demonstrated this with a proof-of-concept program responsibly disclosed off-list.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 30eae2b037af54b24109dcaea21db46f6285c69b , < 672b526def1f94c1be8eb11b885b803da0d8c2f1 (git)
Affected: 30eae2b037af54b24109dcaea21db46f6285c69b , < 30ab358fad0c7daa1d282ec48089901b21b36a20 (git)
Affected: 30eae2b037af54b24109dcaea21db46f6285c69b , < 206121294b9cf27f0589857f80d64f87e496ffb2 (git)
Affected: 30eae2b037af54b24109dcaea21db46f6285c69b , < 7fb4dadc2734f4020d7543d688b8d49c8e569c61 (git)
Affected: 30eae2b037af54b24109dcaea21db46f6285c69b , < d702c3408213bb12bd570bb97204d8340d141c51 (git)
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    Linux Linux Affected: 6.4
Unaffected: 0 , < 6.4 (semver)
Unaffected: 6.6.135 , ≤ 6.6.* (semver)
Unaffected: 6.12.82 , ≤ 6.12.* (semver)
Unaffected: 6.18.23 , ≤ 6.18.* (semver)
Unaffected: 6.19.13 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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{
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          "product": "Linux",
          "programFiles": [
            "crypto/asymmetric_keys/x509_cert_parser.c"
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      "cpeApplicability": [
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nX.509: Fix out-of-bounds access when parsing extensions\n\nLeo reports an out-of-bounds access when parsing a certificate with\nempty Basic Constraints or Key Usage extension because the first byte of\nthe extension is read before checking its length.  Fix it.\n\nThe bug can be triggered by an unprivileged user by submitting a\nspecially crafted certificate to the kernel through the keyrings(7) API.\nLeo has demonstrated this with a proof-of-concept program responsibly\ndisclosed off-list."
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        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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    "cveId": "CVE-2026-31430",
    "datePublished": "2026-04-20T09:43:03.919Z",
    "dateReserved": "2026-03-09T15:48:24.089Z",
    "dateUpdated": "2026-04-20T09:43:03.919Z",
    "state": "PUBLISHED"
  },
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  }
}


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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.



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