{"id":"CVE-2021-47356","state":"PUBLISHED","title":"mISDN: fix possible use-after-free in HFC_cleanup()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmISDN: fix possible use-after-free in HFC_cleanup()\n\nThis module's remove path calls del_timer(). However, that function\ndoes not wait until the timer handler finishes. This means that the\ntimer handler may still be running after the driver's remove function\nhas finished, which would result in a use-after-free.\n\nFix by calling del_timer_sync(), which makes sure the timer handler\nhas finished, and unable to re-schedule itself.","publishedAt":"2024-05-21T14:35:59.097Z","updatedAt":"2026-05-11T13:53:07.476Z","severity":{"score":7.7,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","source":"CISA-ADP"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"87c5fa1bb42624254a2013cbbc3b170d6017f5d6","status":"affected","lessThan":"49331c07ef0f8fdfa42b30ba6a83a657b29d7fbe","versionType":"git"},{"version":"87c5fa1bb42624254a2013cbbc3b170d6017f5d6","status":"affected","lessThan":"54ff3202928952a100c477248e65ac6db01258a7","versionType":"git"},{"version":"87c5fa1bb42624254a2013cbbc3b170d6017f5d6","status":"affected","lessThan":"7867ddc5f3de7f289aee63233afc0df4b62834c5","versionType":"git"},{"version":"87c5fa1bb42624254a2013cbbc3b170d6017f5d6","status":"affected","lessThan":"5f2818185da0fe82a932f0856633038b66faf124","versionType":"git"},{"version":"87c5fa1bb42624254a2013cbbc3b170d6017f5d6","status":"affected","lessThan":"3ecd228c636ee17c14662729737fa07242a93cb0","versionType":"git"},{"version":"87c5fa1bb42624254a2013cbbc3b170d6017f5d6","status":"affected","lessThan":"b7ee9ae1e0cf55a037c4a99af2acc5d78cb7802d","versionType":"git"},{"version":"87c5fa1bb42624254a2013cbbc3b170d6017f5d6","status":"affected","lessThan":"61370ff07e0acc657559a8fac02551dfeb9d3020","versionType":"git"},{"version":"87c5fa1bb42624254a2013cbbc3b170d6017f5d6","status":"affected","lessThan":"ed7c3739d0a07e2ec3ccbffe7e93cea01c438cda","versionType":"git"},{"version":"87c5fa1bb42624254a2013cbbc3b170d6017f5d6","status":"affected","lessThan":"009fc857c5f6fda81f2f7dd851b2d54193a8e733","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/isdn/hardware/mISDN/hfcpci.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.29","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.29","versionType":"semver"},{"version":"4.4.276","status":"unaffected","lessThanOrEqual":"4.4.*","versionType":"semver"},{"version":"4.9.276","status":"unaffected","lessThanOrEqual":"4.9.*","versionType":"semver"},{"version":"4.14.240","status":"unaffected","lessThanOrEqual":"4.14.*","versionType":"semver"},{"version":"4.19.198","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.133","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.51","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.12.18","status":"unaffected","lessThanOrEqual":"5.12.*","versionType":"semver"},{"version":"5.13.3","status":"unaffected","lessThanOrEqual":"5.13.*","versionType":"semver"},{"version":"5.14","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/isdn/hardware/mISDN/hfcpci.c"]}],"references":["https://git.kernel.org/stable/c/49331c07ef0f8fdfa42b30ba6a83a657b29d7fbe","https://git.kernel.org/stable/c/54ff3202928952a100c477248e65ac6db01258a7","https://git.kernel.org/stable/c/7867ddc5f3de7f289aee63233afc0df4b62834c5","https://git.kernel.org/stable/c/5f2818185da0fe82a932f0856633038b66faf124","https://git.kernel.org/stable/c/3ecd228c636ee17c14662729737fa07242a93cb0","https://git.kernel.org/stable/c/b7ee9ae1e0cf55a037c4a99af2acc5d78cb7802d","https://git.kernel.org/stable/c/61370ff07e0acc657559a8fac02551dfeb9d3020","https://git.kernel.org/stable/c/ed7c3739d0a07e2ec3ccbffe7e93cea01c438cda","https://git.kernel.org/stable/c/009fc857c5f6fda81f2f7dd851b2d54193a8e733"],"weaknesses":["CWE-416"],"ingestedAt":"2026-10-29T19:49:19.404Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2021/47xxx/CVE-2021-47356.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2021-47356","state":"PUBLISHED","datePublished":"2024-05-21T14:35:59.097Z","dateUpdated":"2026-05-11T13:53:07.476Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2024-05-21T14:28:16.987Z"},"containers":{"cna":{"title":"mISDN: fix possible use-after-free in HFC_cleanup()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmISDN: fix possible use-after-free in HFC_cleanup()\n\nThis module's remove path calls del_timer(). However, that function\ndoes not wait until the timer handler finishes. This means that the\ntimer handler may still be running after the driver's remove function\nhas finished, which would result in a use-after-free.\n\nFix by calling del_timer_sync(), which makes sure the timer handler\nhas finished, and unable to re-schedule itself."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"87c5fa1bb42624254a2013cbbc3b170d6017f5d6","status":"affected","lessThan":"49331c07ef0f8fdfa42b30ba6a83a657b29d7fbe","versionType":"git"},{"version":"87c5fa1bb42624254a2013cbbc3b170d6017f5d6","status":"affected","lessThan":"54ff3202928952a100c477248e65ac6db01258a7","versionType":"git"},{"version":"87c5fa1bb42624254a2013cbbc3b170d6017f5d6","status":"affected","lessThan":"7867ddc5f3de7f289aee63233afc0df4b62834c5","versionType":"git"},{"version":"87c5fa1bb42624254a2013cbbc3b170d6017f5d6","status":"affected","lessThan":"5f2818185da0fe82a932f0856633038b66faf124","versionType":"git"},{"version":"87c5fa1bb42624254a2013cbbc3b170d6017f5d6","status":"affected","lessThan":"3ecd228c636ee17c14662729737fa07242a93cb0","versionType":"git"},{"version":"87c5fa1bb42624254a2013cbbc3b170d6017f5d6","status":"affected","lessThan":"b7ee9ae1e0cf55a037c4a99af2acc5d78cb7802d","versionType":"git"},{"version":"87c5fa1bb42624254a2013cbbc3b170d6017f5d6","status":"affected","lessThan":"61370ff07e0acc657559a8fac02551dfeb9d3020","versionType":"git"},{"version":"87c5fa1bb42624254a2013cbbc3b170d6017f5d6","status":"affected","lessThan":"ed7c3739d0a07e2ec3ccbffe7e93cea01c438cda","versionType":"git"},{"version":"87c5fa1bb42624254a2013cbbc3b170d6017f5d6","status":"affected","lessThan":"009fc857c5f6fda81f2f7dd851b2d54193a8e733","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/isdn/hardware/mISDN/hfcpci.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.29","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.29","versionType":"semver"},{"version":"4.4.276","status":"unaffected","lessThanOrEqual":"4.4.*","versionType":"semver"},{"version":"4.9.276","status":"unaffected","lessThanOrEqual":"4.9.*","versionType":"semver"},{"version":"4.14.240","status":"unaffected","lessThanOrEqual":"4.14.*","versionType":"semver"},{"version":"4.19.198","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.133","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.51","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.12.18","status":"unaffected","lessThanOrEqual":"5.12.*","versionType":"semver"},{"version":"5.13.3","status":"unaffected","lessThanOrEqual":"5.13.*","versionType":"semver"},{"version":"5.14","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/isdn/hardware/mISDN/hfcpci.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/49331c07ef0f8fdfa42b30ba6a83a657b29d7fbe"},{"url":"https://git.kernel.org/stable/c/54ff3202928952a100c477248e65ac6db01258a7"},{"url":"https://git.kernel.org/stable/c/7867ddc5f3de7f289aee63233afc0df4b62834c5"},{"url":"https://git.kernel.org/stable/c/5f2818185da0fe82a932f0856633038b66faf124"},{"url":"https://git.kernel.org/stable/c/3ecd228c636ee17c14662729737fa07242a93cb0"},{"url":"https://git.kernel.org/stable/c/b7ee9ae1e0cf55a037c4a99af2acc5d78cb7802d"},{"url":"https://git.kernel.org/stable/c/61370ff07e0acc657559a8fac02551dfeb9d3020"},{"url":"https://git.kernel.org/stable/c/ed7c3739d0a07e2ec3ccbffe7e93cea01c438cda"},{"url":"https://git.kernel.org/stable/c/009fc857c5f6fda81f2f7dd851b2d54193a8e733"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-05-11T13:53:07.476Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"4.4.276"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"4.9.276"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"4.14.240"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"4.19.198"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"5.4.133"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"5.10.51"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"5.12.18"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"5.13.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"5.14"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","affected":[{"vendor":"linux","product":"linux_kernel","defaultStatus":"unknown","versions":[{"version":"1da177e4c3f4","status":"affected","lessThan":"49331c07ef0f","versionType":"custom"}],"cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"]},{"vendor":"linux","product":"linux_kernel","defaultStatus":"unknown","versions":[{"version":"1da177e4c3f4","status":"affected","lessThan":"54ff32029289","versionType":"custom"}],"cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"]},{"vendor":"linux","product":"linux_kernel","defaultStatus":"unknown","versions":[{"version":"1da177e4c3f4","status":"affected","lessThan":"7867ddc5f3de","versionType":"custom"}],"cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"]},{"vendor":"linux","product":"linux_kernel","defaultStatus":"unknown","versions":[{"version":"1da177e4c3f4","status":"affected","lessThan":"5f2818185da0","versionType":"custom"}],"cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"]},{"vendor":"linux","product":"linux_kernel","defaultStatus":"unknown","versions":[{"version":"1da177e4c3f4","status":"affected","lessThan":"3ecd228c636e","versionType":"custom"}],"cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"]},{"vendor":"linux","product":"linux_kernel","defaultStatus":"unknown","versions":[{"version":"1da177e4c3f4","status":"affected","lessThan":"b7ee9ae1e0cf","versionType":"custom"}],"cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"]},{"vendor":"linux","product":"linux_kernel","defaultStatus":"unknown","versions":[{"version":"1da177e4c3f4","status":"affected","lessThan":"61370ff07e0a","versionType":"custom"}],"cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"]},{"vendor":"linux","product":"linux_kernel","defaultStatus":"unknown","versions":[{"version":"1da177e4c3f4","status":"affected","lessThan":"ed7c3739d0a0","versionType":"custom"}],"cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"]},{"vendor":"linux","product":"linux_kernel","defaultStatus":"unknown","versions":[{"version":"1da177e4c3f4","status":"affected","lessThan":"009fc857c5f6","versionType":"custom"}],"cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"]},{"vendor":"linux","product":"linux_kernel","defaultStatus":"unknown","versions":[{"version":"4.4.276","status":"unaffected","lessThanOrEqual":"4.4.*","versionType":"custom"}],"cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"]},{"vendor":"linux","product":"linux_kernel","defaultStatus":"unknown","versions":[{"version":"4.9.276","status":"unaffected","lessThanOrEqual":"4.9.*","versionType":"custom"}],"cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"]},{"vendor":"linux","product":"linux_kernel","defaultStatus":"unknown","versions":[{"version":"4.14.240","status":"unaffected","lessThanOrEqual":"4.14.*","versionType":"custom"}],"cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"]},{"vendor":"linux","product":"linux_kernel","defaultStatus":"unknown","versions":[{"version":"4.19.198","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"custom"}],"cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"]},{"vendor":"linux","product":"linux_kernel","defaultStatus":"unknown","versions":[{"version":"5.4.133","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"custom"}],"cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"]},{"vendor":"linux","product":"linux_kernel","defaultStatus":"unknown","versions":[{"version":"5.10.51","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"custom"}],"cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"]},{"vendor":"linux","product":"linux_kernel","defaultStatus":"unknown","versions":[{"version":"5.12.18","status":"unaffected","lessThanOrEqual":"5.12.*","versionType":"custom"}],"cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"]},{"vendor":"linux","product":"linux_kernel","defaultStatus":"unknown","versions":[{"version":"5.13.3","status":"unaffected","lessThanOrEqual":"5.13.*","versionType":"custom"}],"cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"]},{"vendor":"linux","product":"linux_kernel","defaultStatus":"unknown","versions":[{"version":"5.14","status":"unaffected"}],"cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"]}],"metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":7.7,"attackVector":"LOCAL","baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","integrityImpact":"HIGH","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"HIGH","privilegesRequired":"NONE","confidentialityImpact":"NONE"}},{"other":{"type":"ssvc","content":{"timestamp":"2025-01-16T21:04:48.759363Z","id":"CVE-2021-47356","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-416","type":"CWE","lang":"en","description":"CWE-416 Use After Free"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2025-01-16T21:05:18.885Z"}},{"title":"CVE Program Container","references":[{"url":"https://git.kernel.org/stable/c/49331c07ef0f8fdfa42b30ba6a83a657b29d7fbe","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/54ff3202928952a100c477248e65ac6db01258a7","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/7867ddc5f3de7f289aee63233afc0df4b62834c5","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/5f2818185da0fe82a932f0856633038b66faf124","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/3ecd228c636ee17c14662729737fa07242a93cb0","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/b7ee9ae1e0cf55a037c4a99af2acc5d78cb7802d","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/61370ff07e0acc657559a8fac02551dfeb9d3020","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/ed7c3739d0a07e2ec3ccbffe7e93cea01c438cda","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/009fc857c5f6fda81f2f7dd851b2d54193a8e733","tags":["x_transferred"]}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2024-08-04T05:32:08.504Z"}}]}}}