CVE-2024-56721 (GCVE-0-2024-56721)

Vulnerability from cvelistv5 – Published: 2024-12-29 11:29 – Updated: 2026-08-05 11:46
VLAI
Title
x86/CPU/AMD: Terminate the erratum_1386_microcode array
Summary
In the Linux kernel, the following vulnerability has been resolved: x86/CPU/AMD: Terminate the erratum_1386_microcode array The erratum_1386_microcode array requires an empty entry at the end. Otherwise x86_match_cpu_with_stepping() will continue iterate the array after it ended. Add an empty entry to erratum_1386_microcode to its end.
Severity
7.1 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2025-10-01 19:58 UTC
CWE
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 29ba89f1895285f06c333546882e0c5ae9a6df23 , < 82d6b82cf89d950982ac240ba068c3a7e1f23b0a (git)
Affected: 29ba89f1895285f06c333546882e0c5ae9a6df23 , < ccfee14f08b8699132b87bc6d78e0fa75bf094dd (git)
Affected: 29ba89f1895285f06c333546882e0c5ae9a6df23 , < ff6cdc407f4179748f4673c39b0921503199a0ad (git)
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Linux Linux Affected: 6.10
Unaffected: 0 , < 6.10 (semver)
Unaffected: 6.11.11 , ≤ 6.11.* (semver)
Unaffected: 6.12.2 , ≤ 6.12.* (semver)
Unaffected: 6.13 , ≤ * (original_commit_for_fix)
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      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 7.1, \"attackVector\": \"LOCAL\", \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H\", \"integrityImpact\": \"NONE\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"LOW\", \"confidentialityImpact\": \"HIGH\"}}, {\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2024-56721\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2025-10-01T19:58:17.697625Z\"}}}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-125\", \"description\": \"CWE-125 Out-of-bounds Read\"}]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2025-10-01T15:48:14.374Z\"}}], \"cna\": {\"title\": \"x86/CPU/AMD: Terminate the erratum_1386_microcode array\", \"metrics\": [{\"cvssV3_1\": {\"version\": \"3.1\", \"baseScore\": 7.1, \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H\"}, \"scenarios\": [{\"lang\": \"en\", \"value\": \"AV:L - `fix_erratum_1386()` runs from `init_amd_zen1()`/`init_amd_zen2()` during `identify_cpu()` at boot and on CPU onlining; there is no remote or adjacent input path, and the resulting misbehaviour is only observable to software running locally on the affected AMD Zen1/Zen2 machine.\\nAC:L - On any family 0x17 CPU whose model/stepping does not match the two table entries, `x86_match_cpu_with_stepping()` runs past the array end on every single boot \\u2014 deterministic, no race to win and no special preconditions.\\nPR:L - The faulty walk executes automatically during CPU identification before any authentication exists, and observing or leveraging the consequences (skipped XSAVES erratum workaround, corrupted XMM state) needs only ordinary unprivileged local access; matches the CNA scoring of the identical bug in CVE-2025-37751.\\nUI:N - The out-of-bounds walk happens automatically as part of boot-time CPU feature initialization and CPU hotplug; no victim action of any kind is involved.\\nS:U - The out-of-bounds read and its consequences are entirely contained within the kernel\u0027s own security authority; no VM, IOMMU, or sandbox boundary is crossed.\\nC:H - The loop performs an unbounded out-of-bounds read of whatever kernel `.rodata` follows `erratum_1386_microcode[]`, with no upper limit on how far it reads, and that out-of-bounds data is then consumed as CPU descriptor/microcode-revision values; additionally, wrongly skipping the erratum 1386 workaround leaves XSAVES able to expose stale XMM register contents across context switches.\\nI:N - The defect is a read-only over-read \\u2014 nothing is written outside the array bounds and no attacker-controlled data is stored \\u2014 matching the I:N assigned to the identical `erratum_1386_microcode` terminator bug (CVE-2025-37751).\\nA:H - The walk continues arbitrarily far past the array until it randomly encounters an entry with zero family and model, so depending on linker layout it can fault or trip UBSAN/KASAN and oops during early boot \\u2014 exactly the boot-time crash seen with the analogous missing-sentinel errata arrays (CVE-2025-37929).\"}]}], \"affected\": [{\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"29ba89f1895285f06c333546882e0c5ae9a6df23\", \"lessThan\": \"82d6b82cf89d950982ac240ba068c3a7e1f23b0a\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"29ba89f1895285f06c333546882e0c5ae9a6df23\", \"lessThan\": \"ccfee14f08b8699132b87bc6d78e0fa75bf094dd\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"29ba89f1895285f06c333546882e0c5ae9a6df23\", \"lessThan\": \"ff6cdc407f4179748f4673c39b0921503199a0ad\", \"versionType\": \"git\"}], \"programFiles\": [\"arch/x86/kernel/cpu/amd.c\"], \"defaultStatus\": \"unaffected\"}, {\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"6.10\"}, {\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"6.10\", \"versionType\": \"semver\"}, {\"status\": \"unaffected\", \"version\": \"6.11.11\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.11.*\"}, {\"status\": \"unaffected\", \"version\": \"6.12.2\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.12.*\"}, {\"status\": \"unaffected\", \"version\": \"6.13\", \"versionType\": \"original_commit_for_fix\", \"lessThanOrEqual\": \"*\"}], \"programFiles\": [\"arch/x86/kernel/cpu/amd.c\"], \"defaultStatus\": \"affected\"}], \"references\": [{\"url\": \"https://git.kernel.org/stable/c/82d6b82cf89d950982ac240ba068c3a7e1f23b0a\"}, {\"url\": \"https://git.kernel.org/stable/c/ccfee14f08b8699132b87bc6d78e0fa75bf094dd\"}, {\"url\": \"https://git.kernel.org/stable/c/ff6cdc407f4179748f4673c39b0921503199a0ad\"}], \"x_generator\": {\"engine\": \"bippy-1.2.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"In the Linux kernel, the following vulnerability has been resolved:\\n\\nx86/CPU/AMD: Terminate the erratum_1386_microcode array\\n\\nThe erratum_1386_microcode array requires an empty entry at the end.\\nOtherwise x86_match_cpu_with_stepping() will continue iterate the array after\\nit ended.\\n\\nAdd an empty entry to erratum_1386_microcode to its end.\"}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.11.11\", \"versionStartIncluding\": \"6.10\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.12.2\", \"versionStartIncluding\": \"6.10\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.13\", \"versionStartIncluding\": \"6.10\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2026-08-05T11:46:19.207Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2024-56721\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-08-05T11:46:19.207Z\", \"dateReserved\": \"2024-12-27T15:00:39.858Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2024-12-29T11:29:59.164Z\", \"assignerShortName\": \"Linux\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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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.


Detection rules are retrieved from Rulezet.