{"id":"CVE-2021-47641","state":"PUBLISHED","title":"video: fbdev: cirrusfb: check pixclock to avoid divide by zero","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nvideo: fbdev: cirrusfb: check pixclock to avoid divide by zero\n\nDo a sanity check on pixclock value to avoid divide by zero.\n\nIf the pixclock value is zero, the cirrusfb driver will round up\npixclock to get the derived frequency as close to maxclock as\npossible.\n\nSyzkaller reported a divide error in cirrusfb_check_pixclock.\n\ndivide error: 0000 [#1] SMP KASAN PTI\nCPU: 0 PID: 14938 Comm: cirrusfb_test Not tainted 5.15.0-rc6 #1\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2\nRIP: 0010:cirrusfb_check_var+0x6f1/0x1260\n\nCall Trace:\n fb_set_var+0x398/0xf90\n do_fb_ioctl+0x4b8/0x6f0\n fb_ioctl+0xeb/0x130\n __x64_sys_ioctl+0x19d/0x220\n do_syscall_64+0x3a/0x80\n entry_SYSCALL_64_after_hwframe+0x44/0xae","publishedAt":"2025-02-26T01:54:12.680Z","updatedAt":"2026-05-11T13:58:19.521Z","severity":{"score":5.5,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","source":"CISA-ADP"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"c656d04247a2654ede5cead2ecbf83431dad5261","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"1d3fb46439ad4e8f0c5739eb33d1875ac9e0f135","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"40b13e3d85744210db13457785646634e2d056bd","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"53a2088a396cfa1da92690a1da289634cd73bf0d","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"8c7e2141fb89c620ab4e41512e262fbf25b8260d","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"6fe23ff94e7840097202e85c148688940b37c9b1","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"45800c42ef000f417270bcfc08630e42486fca99","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"e498b504f8c81b07efab9febf8503448de4dc9cf","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"5c6f402bdcf9e7239c6bc7087eda71ac99b31379","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/video/fbdev/cirrusfb.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.12","versionType":"semver"},{"version":"4.9.311","status":"unaffected","lessThanOrEqual":"4.9.*","versionType":"semver"},{"version":"4.14.276","status":"unaffected","lessThanOrEqual":"4.14.*","versionType":"semver"},{"version":"4.19.238","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.189","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.110","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.33","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"5.16.19","status":"unaffected","lessThanOrEqual":"5.16.*","versionType":"semver"},{"version":"5.17.2","status":"unaffected","lessThanOrEqual":"5.17.*","versionType":"semver"},{"version":"5.18","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/video/fbdev/cirrusfb.c"]}],"references":["https://git.kernel.org/stable/c/c656d04247a2654ede5cead2ecbf83431dad5261","https://git.kernel.org/stable/c/1d3fb46439ad4e8f0c5739eb33d1875ac9e0f135","https://git.kernel.org/stable/c/40b13e3d85744210db13457785646634e2d056bd","https://git.kernel.org/stable/c/53a2088a396cfa1da92690a1da289634cd73bf0d","https://git.kernel.org/stable/c/8c7e2141fb89c620ab4e41512e262fbf25b8260d","https://git.kernel.org/stable/c/6fe23ff94e7840097202e85c148688940b37c9b1","https://git.kernel.org/stable/c/45800c42ef000f417270bcfc08630e42486fca99","https://git.kernel.org/stable/c/e498b504f8c81b07efab9febf8503448de4dc9cf","https://git.kernel.org/stable/c/5c6f402bdcf9e7239c6bc7087eda71ac99b31379"],"weaknesses":["CWE-369"],"ingestedAt":"2026-10-29T19:49:19.404Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2021/47xxx/CVE-2021-47641.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2021-47641","state":"PUBLISHED","datePublished":"2025-02-26T01:54:12.680Z","dateUpdated":"2026-05-11T13:58:19.521Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-02-26T01:48:21.519Z"},"containers":{"cna":{"title":"video: fbdev: cirrusfb: check pixclock to avoid divide by zero","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nvideo: fbdev: cirrusfb: check pixclock to avoid divide by zero\n\nDo a sanity check on pixclock value to avoid divide by zero.\n\nIf the pixclock value is zero, the cirrusfb driver will round up\npixclock to get the derived frequency as close to maxclock as\npossible.\n\nSyzkaller reported a divide error in cirrusfb_check_pixclock.\n\ndivide error: 0000 [#1] SMP KASAN PTI\nCPU: 0 PID: 14938 Comm: cirrusfb_test Not tainted 5.15.0-rc6 #1\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2\nRIP: 0010:cirrusfb_check_var+0x6f1/0x1260\n\nCall Trace:\n fb_set_var+0x398/0xf90\n do_fb_ioctl+0x4b8/0x6f0\n fb_ioctl+0xeb/0x130\n __x64_sys_ioctl+0x19d/0x220\n do_syscall_64+0x3a/0x80\n entry_SYSCALL_64_after_hwframe+0x44/0xae"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"c656d04247a2654ede5cead2ecbf83431dad5261","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"1d3fb46439ad4e8f0c5739eb33d1875ac9e0f135","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"40b13e3d85744210db13457785646634e2d056bd","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"53a2088a396cfa1da92690a1da289634cd73bf0d","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"8c7e2141fb89c620ab4e41512e262fbf25b8260d","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"6fe23ff94e7840097202e85c148688940b37c9b1","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"45800c42ef000f417270bcfc08630e42486fca99","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"e498b504f8c81b07efab9febf8503448de4dc9cf","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"5c6f402bdcf9e7239c6bc7087eda71ac99b31379","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/video/fbdev/cirrusfb.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.12","versionType":"semver"},{"version":"4.9.311","status":"unaffected","lessThanOrEqual":"4.9.*","versionType":"semver"},{"version":"4.14.276","status":"unaffected","lessThanOrEqual":"4.14.*","versionType":"semver"},{"version":"4.19.238","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.189","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.110","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.33","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"5.16.19","status":"unaffected","lessThanOrEqual":"5.16.*","versionType":"semver"},{"version":"5.17.2","status":"unaffected","lessThanOrEqual":"5.17.*","versionType":"semver"},{"version":"5.18","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/video/fbdev/cirrusfb.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/c656d04247a2654ede5cead2ecbf83431dad5261"},{"url":"https://git.kernel.org/stable/c/1d3fb46439ad4e8f0c5739eb33d1875ac9e0f135"},{"url":"https://git.kernel.org/stable/c/40b13e3d85744210db13457785646634e2d056bd"},{"url":"https://git.kernel.org/stable/c/53a2088a396cfa1da92690a1da289634cd73bf0d"},{"url":"https://git.kernel.org/stable/c/8c7e2141fb89c620ab4e41512e262fbf25b8260d"},{"url":"https://git.kernel.org/stable/c/6fe23ff94e7840097202e85c148688940b37c9b1"},{"url":"https://git.kernel.org/stable/c/45800c42ef000f417270bcfc08630e42486fca99"},{"url":"https://git.kernel.org/stable/c/e498b504f8c81b07efab9febf8503448de4dc9cf"},{"url":"https://git.kernel.org/stable/c/5c6f402bdcf9e7239c6bc7087eda71ac99b31379"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-05-11T13:58:19.521Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"4.9.311"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"4.14.276"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"4.19.238"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"5.4.189"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"5.10.110"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"5.15.33"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"5.16.19"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"5.17.2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"5.18"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":5.5,"attackVector":"LOCAL","baseSeverity":"MEDIUM","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","integrityImpact":"NONE","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"HIGH","privilegesRequired":"LOW","confidentialityImpact":"NONE"}},{"other":{"type":"ssvc","content":{"id":"CVE-2021-47641","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2025-10-01T19:50:40.514584Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-369","lang":"en","type":"CWE","description":"CWE-369 Divide By Zero"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2025-10-01T19:57:08.118Z"}}]}}}