CVE-2024-42240 (GCVE-0-2024-42240)

Vulnerability from cvelistv5 – Published: 2024-08-07 15:14 – Updated: 2026-05-11 20:28
VLAI?
Title
x86/bhi: Avoid warning in #DB handler due to BHI mitigation
Summary
In the Linux kernel, the following vulnerability has been resolved: x86/bhi: Avoid warning in #DB handler due to BHI mitigation When BHI mitigation is enabled, if SYSENTER is invoked with the TF flag set then entry_SYSENTER_compat() uses CLEAR_BRANCH_HISTORY and calls the clear_bhb_loop() before the TF flag is cleared. This causes the #DB handler (exc_debug_kernel()) to issue a warning because single-step is used outside the entry_SYSENTER_compat() function. To address this issue, entry_SYSENTER_compat() should use CLEAR_BRANCH_HISTORY after making sure the TF flag is cleared. The problem can be reproduced with the following sequence: $ cat sysenter_step.c int main() { asm("pushf; pop %ax; bts $8,%ax; push %ax; popf; sysenter"); } $ gcc -o sysenter_step sysenter_step.c $ ./sysenter_step Segmentation fault (core dumped) The program is expected to crash, and the #DB handler will issue a warning. Kernel log: WARNING: CPU: 27 PID: 7000 at arch/x86/kernel/traps.c:1009 exc_debug_kernel+0xd2/0x160 ... RIP: 0010:exc_debug_kernel+0xd2/0x160 ... Call Trace: <#DB> ? show_regs+0x68/0x80 ? __warn+0x8c/0x140 ? exc_debug_kernel+0xd2/0x160 ? report_bug+0x175/0x1a0 ? handle_bug+0x44/0x90 ? exc_invalid_op+0x1c/0x70 ? asm_exc_invalid_op+0x1f/0x30 ? exc_debug_kernel+0xd2/0x160 exc_debug+0x43/0x50 asm_exc_debug+0x1e/0x40 RIP: 0010:clear_bhb_loop+0x0/0xb0 ... </#DB> <TASK> ? entry_SYSENTER_compat_after_hwframe+0x6e/0x8d </TASK> [ bp: Massage commit message. ]
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: bd53ec80f21839cfd4d852a6088279d602d67e5b , < db56615e96c439e13783d7715330e824b4fd4b84 (git)
Affected: 07dbb10f153f483e8249acebdffedf922e2ec2e1 , < a765679defe1dc1b8fa01928a6ad6361e72a1364 (git)
Affected: eb36b0dce2138581bc6b5e39d0273cb4c96ded81 , < dae3543db8f0cf8ac1a198c3bb4b6e3c24d576cf (git)
Affected: 7390db8aea0d64e9deb28b8e1ce716f5020c7ee5 , < 08518d48e5b744620524f0acd7c26c19bda7f513 (git)
Affected: 7390db8aea0d64e9deb28b8e1ce716f5020c7ee5 , < ac8b270b61d48fcc61f052097777e3b5e11591e0 (git)
Affected: 8f51637712e4da5be410a1666f8aee0d86eef898 (git)
Create a notification for this product.
Linux Linux Affected: 6.9
Unaffected: 0 , < 6.9 (semver)
Unaffected: 5.15.163 , ≤ 5.15.* (semver)
Unaffected: 6.1.100 , ≤ 6.1.* (semver)
Unaffected: 6.6.41 , ≤ 6.6.* (semver)
Unaffected: 6.9.10 , ≤ 6.9.* (semver)
Unaffected: 6.10 , ≤ * (original_commit_for_fix)
Create a notification for this product.
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      "id": "CVE-2024-42240",
      "lastModified": "2024-08-08T14:53:59.897",
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    "nvd": "{\"cve\":{\"id\":\"CVE-2024-42240\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2024-08-07T16:15:46.810\",\"lastModified\":\"2025-11-03T22:17:49.327\",\"vulnStatus\":\"Modified\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nx86/bhi: Avoid warning in #DB handler due to BHI mitigation\\n\\nWhen BHI mitigation is enabled, if SYSENTER is invoked with the TF flag set\\nthen entry_SYSENTER_compat() uses CLEAR_BRANCH_HISTORY and calls the\\nclear_bhb_loop() before the TF flag is cleared. This causes the #DB handler\\n(exc_debug_kernel()) to issue a warning because single-step is used outside the\\nentry_SYSENTER_compat() function.\\n\\nTo address this issue, entry_SYSENTER_compat() should use CLEAR_BRANCH_HISTORY\\nafter making sure the TF flag is cleared.\\n\\nThe problem can be reproduced with the following sequence:\\n\\n  $ cat sysenter_step.c\\n  int main()\\n  { asm(\\\"pushf; pop %ax; bts $8,%ax; push %ax; popf; sysenter\\\"); }\\n\\n  $ gcc -o sysenter_step sysenter_step.c\\n\\n  $ ./sysenter_step\\n  Segmentation fault (core dumped)\\n\\nThe program is expected to crash, and the #DB handler will issue a warning.\\n\\nKernel log:\\n\\n  WARNING: CPU: 27 PID: 7000 at arch/x86/kernel/traps.c:1009 exc_debug_kernel+0xd2/0x160\\n  ...\\n  RIP: 0010:exc_debug_kernel+0xd2/0x160\\n  ...\\n  Call Trace:\\n  \u003c#DB\u003e\\n   ? show_regs+0x68/0x80\\n   ? __warn+0x8c/0x140\\n   ? exc_debug_kernel+0xd2/0x160\\n   ? report_bug+0x175/0x1a0\\n   ? handle_bug+0x44/0x90\\n   ? exc_invalid_op+0x1c/0x70\\n   ? asm_exc_invalid_op+0x1f/0x30\\n   ? exc_debug_kernel+0xd2/0x160\\n   exc_debug+0x43/0x50\\n   asm_exc_debug+0x1e/0x40\\n  RIP: 0010:clear_bhb_loop+0x0/0xb0\\n  ...\\n  \u003c/#DB\u003e\\n  \u003cTASK\u003e\\n   ? entry_SYSENTER_compat_after_hwframe+0x6e/0x8d\\n  \u003c/TASK\u003e\\n\\n  [ bp: Massage commit message. ]\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: x86/bhi: evitar advertencia en el controlador #DB debido a la mitigaci\u00f3n de BHI Cuando la mitigaci\u00f3n de BHI est\u00e1 habilitada, si se invoca SYSENTER con el indicador TF configurado, entonces Entry_SYSENTER_compat() usa CLEAR_BRANCH_HISTORY y llama al clear_bhb_loop() antes de que se borre la bandera TF. Esto hace que el controlador #DB (exc_debug_kernel()) emita una advertencia porque se utiliza un solo paso fuera de la funci\u00f3n Entry_SYSENTER_compat(). Para solucionar este problema, Entry_SYSENTER_compat() debe usar CLEAR_BRANCH_HISTORY despu\u00e9s de asegurarse de que el indicador TF est\u00e9 borrado. El problema se puede reproducir con la siguiente secuencia: $ cat sysenter_step.c int main() { asm(\\\"pushf; pop %ax; bts $8,%ax; push %ax; popf; sysenter\\\"); } $ gcc -o sysenter_step sysenter_step.c $ ./sysenter_step Fallo de segmentaci\u00f3n (n\u00facleo volcado) Se espera que el programa falle y el controlador #DB emitir\u00e1 una advertencia. Registro del kernel: ADVERTENCIA: CPU: 27 PID: 7000 en arch/x86/kernel/traps.c:1009 exc_debug_kernel+0xd2/0x160... RIP: 0010:exc_debug_kernel+0xd2/0x160... Seguimiento de llamadas: \u0026lt;#DB\u0026gt; ? show_regs+0x68/0x80? __advertir+0x8c/0x140 ? exc_debug_kernel+0xd2/0x160? report_bug+0x175/0x1a0? handle_bug+0x44/0x90? exc_invalid_op+0x1c/0x70? asm_exc_invalid_op+0x1f/0x30? exc_debug_kernel+0xd2/0x160 exc_debug+0x43/0x50 asm_exc_debug+0x1e/0x40 RIP: 0010:clear_bhb_loop+0x0/0xb0 ...   ? Entry_SYSENTER_compat_after_hwframe+0x6e/0x8d  [bp: mensaje de commit de masaje. ]\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":5.5,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":3.6}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-835\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"5.15.163\",\"versionEndExcluding\":\"6.1.100\",\"matchCriteriaId\":\"CAAB30CE-506C-42CC-B146-52655F61012E\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.2\",\"versionEndExcluding\":\"6.6.41\",\"matchCriteriaId\":\"96AC42B8-D66D-4AC5-B466-E9BA7910FA29\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.7\",\"versionEndExcluding\":\"6.9.10\",\"matchCriteriaId\":\"AB2E8DEC-CFD5-4C2B-981D-E7E45A36C352\"}]}]}],\"references\":[{\"url\":\"https://git.kernel.org/stable/c/08518d48e5b744620524f0acd7c26c19bda7f513\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/a765679defe1dc1b8fa01928a6ad6361e72a1364\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/ac8b270b61d48fcc61f052097777e3b5e11591e0\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/dae3543db8f0cf8ac1a198c3bb4b6e3c24d576cf\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/db56615e96c439e13783d7715330e824b4fd4b84\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\"}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CVE Program Container\", \"references\": [{\"url\": \"https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html\"}], \"providerMetadata\": {\"orgId\": \"af854a3a-2127-422b-91ae-364da2661108\", \"shortName\": \"CVE\", \"dateUpdated\": \"2025-11-03T22:02:42.210Z\"}}, {\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2024-42240\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2024-09-10T16:13:51.001454Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2024-09-11T12:42:24.229Z\"}}], \"cna\": {\"title\": \"x86/bhi: Avoid warning in #DB handler due to BHI mitigation\", \"affected\": [{\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"bd53ec80f21839cfd4d852a6088279d602d67e5b\", \"lessThan\": \"db56615e96c439e13783d7715330e824b4fd4b84\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"07dbb10f153f483e8249acebdffedf922e2ec2e1\", \"lessThan\": \"a765679defe1dc1b8fa01928a6ad6361e72a1364\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"eb36b0dce2138581bc6b5e39d0273cb4c96ded81\", \"lessThan\": \"dae3543db8f0cf8ac1a198c3bb4b6e3c24d576cf\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"7390db8aea0d64e9deb28b8e1ce716f5020c7ee5\", \"lessThan\": \"08518d48e5b744620524f0acd7c26c19bda7f513\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"7390db8aea0d64e9deb28b8e1ce716f5020c7ee5\", \"lessThan\": \"ac8b270b61d48fcc61f052097777e3b5e11591e0\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"8f51637712e4da5be410a1666f8aee0d86eef898\", \"versionType\": \"git\"}], \"programFiles\": [\"arch/x86/entry/entry_64_compat.S\"], \"defaultStatus\": \"unaffected\"}, {\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"6.9\"}, {\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"6.9\", \"versionType\": \"semver\"}, {\"status\": \"unaffected\", \"version\": \"5.15.163\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.15.*\"}, {\"status\": \"unaffected\", \"version\": \"6.1.100\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.1.*\"}, {\"status\": \"unaffected\", \"version\": \"6.6.41\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.6.*\"}, {\"status\": \"unaffected\", \"version\": \"6.9.10\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"6.9.*\"}, {\"status\": \"unaffected\", \"version\": \"6.10\", \"versionType\": \"original_commit_for_fix\", \"lessThanOrEqual\": \"*\"}], \"programFiles\": [\"arch/x86/entry/entry_64_compat.S\"], \"defaultStatus\": \"affected\"}], \"references\": [{\"url\": \"https://git.kernel.org/stable/c/db56615e96c439e13783d7715330e824b4fd4b84\"}, {\"url\": \"https://git.kernel.org/stable/c/a765679defe1dc1b8fa01928a6ad6361e72a1364\"}, {\"url\": \"https://git.kernel.org/stable/c/dae3543db8f0cf8ac1a198c3bb4b6e3c24d576cf\"}, {\"url\": \"https://git.kernel.org/stable/c/08518d48e5b744620524f0acd7c26c19bda7f513\"}, {\"url\": \"https://git.kernel.org/stable/c/ac8b270b61d48fcc61f052097777e3b5e11591e0\"}], \"x_generator\": {\"engine\": \"bippy-1.2.0\"}, \"descriptions\": [{\"lang\": \"en\", \"value\": \"In the Linux kernel, the following vulnerability has been resolved:\\n\\nx86/bhi: Avoid warning in #DB handler due to BHI mitigation\\n\\nWhen BHI mitigation is enabled, if SYSENTER is invoked with the TF flag set\\nthen entry_SYSENTER_compat() uses CLEAR_BRANCH_HISTORY and calls the\\nclear_bhb_loop() before the TF flag is cleared. This causes the #DB handler\\n(exc_debug_kernel()) to issue a warning because single-step is used outside the\\nentry_SYSENTER_compat() function.\\n\\nTo address this issue, entry_SYSENTER_compat() should use CLEAR_BRANCH_HISTORY\\nafter making sure the TF flag is cleared.\\n\\nThe problem can be reproduced with the following sequence:\\n\\n  $ cat sysenter_step.c\\n  int main()\\n  { asm(\\\"pushf; pop %ax; bts $8,%ax; push %ax; popf; sysenter\\\"); }\\n\\n  $ gcc -o sysenter_step sysenter_step.c\\n\\n  $ ./sysenter_step\\n  Segmentation fault (core dumped)\\n\\nThe program is expected to crash, and the #DB handler will issue a warning.\\n\\nKernel log:\\n\\n  WARNING: CPU: 27 PID: 7000 at arch/x86/kernel/traps.c:1009 exc_debug_kernel+0xd2/0x160\\n  ...\\n  RIP: 0010:exc_debug_kernel+0xd2/0x160\\n  ...\\n  Call Trace:\\n  \u003c#DB\u003e\\n   ? show_regs+0x68/0x80\\n   ? __warn+0x8c/0x140\\n   ? exc_debug_kernel+0xd2/0x160\\n   ? report_bug+0x175/0x1a0\\n   ? handle_bug+0x44/0x90\\n   ? exc_invalid_op+0x1c/0x70\\n   ? asm_exc_invalid_op+0x1f/0x30\\n   ? exc_debug_kernel+0xd2/0x160\\n   exc_debug+0x43/0x50\\n   asm_exc_debug+0x1e/0x40\\n  RIP: 0010:clear_bhb_loop+0x0/0xb0\\n  ...\\n  \u003c/#DB\u003e\\n  \u003cTASK\u003e\\n   ? entry_SYSENTER_compat_after_hwframe+0x6e/0x8d\\n  \u003c/TASK\u003e\\n\\n  [ bp: Massage commit message. ]\"}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.15.163\", \"versionStartIncluding\": \"5.15.154\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.1.100\", \"versionStartIncluding\": \"6.1.85\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.6.41\", \"versionStartIncluding\": \"6.6.26\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.9.10\", \"versionStartIncluding\": \"6.9\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"6.10\", \"versionStartIncluding\": \"6.9\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionStartIncluding\": \"6.8.5\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2025-05-04T12:57:48.564Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2024-42240\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2025-11-03T22:02:42.210Z\", \"dateReserved\": \"2024-07-30T07:40:12.253Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2024-08-07T15:14:27.977Z\", \"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.