{"api_version":"1","generated_at":"2026-07-24T03:32:59+00:00","cve":"CVE-2026-63942","urls":{"html":"https://cve.report/CVE-2026-63942","api":"https://cve.report/api/cve/CVE-2026-63942.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-63942","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-63942"},"summary":{"title":"parport: Fix race between port and client registration","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nparport: Fix race between port and client registration\n\nThe parport subsystem registers port devices before they are fully\ninitialised, resulting in a race condition where client drivers such\nas lp can attach to ports that are not completely initialised or even\nbeing torn down.\n\nWhen the port and client drivers are built as modules and loaded\naround the same time during boot, this occasionally results in a\ncrash.  I was able to make this happen reliably in a VM with a\nPC-style parallel port by patching parport_pc to fail probing:\n\n> --- a/drivers/parport/parport_pc.c\n> +++ b/drivers/parport/parport_pc.c\n> @@ -2069,7 +2069,7 @@ static struct parport *__parport_pc_probe_port(unsigned long int base,\n>  \tif (!p)\n>  \t\tgoto out3;\n>\n> -\tbase_res = request_region(base, 3, p->name);\n> +\tbase_res = NULL;\n>  \tif (!base_res)\n>  \t\tgoto out4;\n>\n\nand then running:\n\n    while true; do\n        modprobe lp & modprobe parport_pc\n\twait\n\trmmod lp parport_pc\n    done\n\nfor a few seconds.\n\nIn the long term I think port registration should be changed to put\nthe call to device_add() inside parport_announce_port(), but since the\nlatter currently cannot fail this will require changing all port\ndrivers.\n\nFor now, add a flag to indicate whether a port has been \"announced\"\nand only try to attach client drivers to ports when the flag is set.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-19 16:17:12","updated_at":"2026-07-20 15:16:57"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/a1e81b58da0179531bedf0b9f2811f5f992d5c4b","name":"https://git.kernel.org/stable/c/a1e81b58da0179531bedf0b9f2811f5f992d5c4b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/290f515c5e3b3900bc2fe24f179999fd08d23bfa","name":"https://git.kernel.org/stable/c/290f515c5e3b3900bc2fe24f179999fd08d23bfa","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/ef15ccbb3e8640a723c42ad90eaf81d66ae02017","name":"https://git.kernel.org/stable/c/ef15ccbb3e8640a723c42ad90eaf81d66ae02017","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d16548be2ea5058227d79799e81dab61c9bca8ec","name":"https://git.kernel.org/stable/c/d16548be2ea5058227d79799e81dab61c9bca8ec","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/74d6aae1df45d3414178986be743f946988fddf6","name":"https://git.kernel.org/stable/c/74d6aae1df45d3414178986be743f946988fddf6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f3378b0d7bd4605de89b083b2900788157a181cc","name":"https://git.kernel.org/stable/c/f3378b0d7bd4605de89b083b2900788157a181cc","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/15b1723c1472e802f9f7e69ae4e64f7dbf588848","name":"https://git.kernel.org/stable/c/15b1723c1472e802f9f7e69ae4e64f7dbf588848","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/51026cff1f4f3b762a0b5a07c727bd59cef45320","name":"https://git.kernel.org/stable/c/51026cff1f4f3b762a0b5a07c727bd59cef45320","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-63942","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63942","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6fa45a22689722dac9f0e90c0931d4b34b334ede f3378b0d7bd4605de89b083b2900788157a181cc git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6fa45a22689722dac9f0e90c0931d4b34b334ede 290f515c5e3b3900bc2fe24f179999fd08d23bfa git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6fa45a22689722dac9f0e90c0931d4b34b334ede d16548be2ea5058227d79799e81dab61c9bca8ec git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6fa45a22689722dac9f0e90c0931d4b34b334ede 15b1723c1472e802f9f7e69ae4e64f7dbf588848 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.210 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.176 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.143 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.93 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.35 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0.12 7.0.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1 * 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the Linux kernel, the following vulnerability has been resolved:\n\nparport: Fix race between port and client registration\n\nThe parport subsystem registers port devices before they are fully\ninitialised, resulting in a race condition where client drivers such\nas lp can attach to ports that are not completely initialised or even\nbeing torn down.\n\nWhen the port and client drivers are built as modules and loaded\naround the same time during boot, this occasionally results in a\ncrash.  I was able to make this happen reliably in a VM with a\nPC-style parallel port by patching parport_pc to fail probing:\n\n> --- a/drivers/parport/parport_pc.c\n> +++ b/drivers/parport/parport_pc.c\n> @@ -2069,7 +2069,7 @@ static struct parport *__parport_pc_probe_port(unsigned long int base,\n>  \tif (!p)\n>  \t\tgoto out3;\n>\n> -\tbase_res = request_region(base, 3, p->name);\n> +\tbase_res = NULL;\n>  \tif (!base_res)\n>  \t\tgoto out4;\n>\n\nand then running:\n\n    while true; do\n        modprobe lp & modprobe parport_pc\n\twait\n\trmmod lp parport_pc\n    done\n\nfor a few seconds.\n\nIn the long term I think port registration should be changed to put\nthe call to device_add() inside parport_announce_port(), but since the\nlatter currently cannot fail this will require changing all port\ndrivers.\n\nFor now, add a flag to indicate whether a port has been \"announced\"\nand only try to attach client drivers to ports when the flag is set."}],"metrics":[{"cvssV3_1":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"providerMetadata":{"dateUpdated":"2026-07-20T13:41:44.057Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/f3378b0d7bd4605de89b083b2900788157a181cc"},{"url":"https://git.kernel.org/stable/c/290f515c5e3b3900bc2fe24f179999fd08d23bfa"},{"url":"https://git.kernel.org/stable/c/d16548be2ea5058227d79799e81dab61c9bca8ec"},{"url":"https://git.kernel.org/stable/c/15b1723c1472e802f9f7e69ae4e64f7dbf588848"},{"url":"https://git.kernel.org/stable/c/51026cff1f4f3b762a0b5a07c727bd59cef45320"},{"url":"https://git.kernel.org/stable/c/74d6aae1df45d3414178986be743f946988fddf6"},{"url":"https://git.kernel.org/stable/c/a1e81b58da0179531bedf0b9f2811f5f992d5c4b"},{"url":"https://git.kernel.org/stable/c/ef15ccbb3e8640a723c42ad90eaf81d66ae02017"}],"title":"parport: Fix race between port and client registration","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-63942","datePublished":"2026-07-19T14:55:37.717Z","dateReserved":"2026-07-19T07:54:57.022Z","dateUpdated":"2026-07-20T13:41:44.057Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-19 16:17:12","lastModifiedDate":"2026-07-20 15:16:57","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"63942","Ordinal":"1","Title":"parport: Fix race between port and client registration","CVE":"CVE-2026-63942","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"63942","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nparport: Fix race between port and client registration\n\nThe parport subsystem registers port devices before they are fully\ninitialised, resulting in a race condition where client drivers such\nas lp can attach to ports that are not completely initialised or even\nbeing torn down.\n\nWhen the port and client drivers are built as modules and loaded\naround the same time during boot, this occasionally results in a\ncrash.  I was able to make this happen reliably in a VM with a\nPC-style parallel port by patching parport_pc to fail probing:\n\n> --- a/drivers/parport/parport_pc.c\n> +++ b/drivers/parport/parport_pc.c\n> @@ -2069,7 +2069,7 @@ static struct parport *__parport_pc_probe_port(unsigned long int base,\n>  \tif (!p)\n>  \t\tgoto out3;\n>\n> -\tbase_res = request_region(base, 3, p->name);\n> +\tbase_res = NULL;\n>  \tif (!base_res)\n>  \t\tgoto out4;\n>\n\nand then running:\n\n    while true; do\n        modprobe lp & modprobe parport_pc\n\twait\n\trmmod lp parport_pc\n    done\n\nfor a few seconds.\n\nIn the long term I think port registration should be changed to put\nthe call to device_add() inside parport_announce_port(), but since the\nlatter currently cannot fail this will require changing all port\ndrivers.\n\nFor now, add a flag to indicate whether a port has been \"announced\"\nand only try to attach client drivers to ports when the flag is set.","Type":"Description","Title":"parport: Fix race between port and client registration"}]}}}