CVE-2021-47641
video: fbdev: cirrusfb: check pixclock to avoid divide by zero
- Published
- Updated
- Reserved
- Assigned by
- Linux
Description
In the Linux kernel, the following vulnerability has been resolved: video: fbdev: cirrusfb: check pixclock to avoid divide by zero Do a sanity check on pixclock value to avoid divide by zero. If the pixclock value is zero, the cirrusfb driver will round up pixclock to get the derived frequency as close to maxclock as possible. Syzkaller reported a divide error in cirrusfb_check_pixclock. divide error: 0000 [#1] SMP KASAN PTI CPU: 0 PID: 14938 Comm: cirrusfb_test Not tainted 5.15.0-rc6 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2 RIP: 0010:cirrusfb_check_var+0x6f1/0x1260 Call Trace: fb_set_var+0x398/0xf90 do_fb_ioctl+0x4b8/0x6f0 fb_ioctl+0xeb/0x130 __x64_sys_ioctl+0x19d/0x220 do_syscall_64+0x3a/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CISA-ADPADP (enrichment) | 3.1 | Medium5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Modified | 3.1 | Medium5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.25% · top 83% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.5.
Weakness
Affected products
- affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – < c656d04247a2654ede5cead2ecbf83431dad5261
- affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – < 1d3fb46439ad4e8f0c5739eb33d1875ac9e0f135
- affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – < 40b13e3d85744210db13457785646634e2d056bd
- affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – < 53a2088a396cfa1da92690a1da289634cd73bf0d
- affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – < 8c7e2141fb89c620ab4e41512e262fbf25b8260d
- affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – < 6fe23ff94e7840097202e85c148688940b37c9b1
- affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – < 45800c42ef000f417270bcfc08630e42486fca99
- affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – < e498b504f8c81b07efab9febf8503448de4dc9cf
- affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 – < 5c6f402bdcf9e7239c6bc7087eda71ac99b31379
- affected 2.6.12
- unaffected < 2.6.12
- unaffected 4.9.311 – ≤ 4.9.*
- unaffected 4.14.276 – ≤ 4.14.*
- unaffected 4.19.238 – ≤ 4.19.*
- unaffected 5.4.189 – ≤ 5.4.*
- unaffected 5.10.110 – ≤ 5.10.*
- unaffected 5.15.33 – ≤ 5.15.*
- unaffected 5.16.19 – ≤ 5.16.*
- unaffected 5.17.2 – ≤ 5.17.*
- unaffected 5.18 – ≤ *
References (9)
- https://git.kernel.org/stable/c/c656d04247a2654ede5cead2ecbf83431dad5261 (opens in a new tab)
- https://git.kernel.org/stable/c/1d3fb46439ad4e8f0c5739eb33d1875ac9e0f135 (opens in a new tab)
- https://git.kernel.org/stable/c/40b13e3d85744210db13457785646634e2d056bd (opens in a new tab)
- https://git.kernel.org/stable/c/53a2088a396cfa1da92690a1da289634cd73bf0d (opens in a new tab)
- https://git.kernel.org/stable/c/8c7e2141fb89c620ab4e41512e262fbf25b8260d (opens in a new tab)
- https://git.kernel.org/stable/c/6fe23ff94e7840097202e85c148688940b37c9b1 (opens in a new tab)
- https://git.kernel.org/stable/c/45800c42ef000f417270bcfc08630e42486fca99 (opens in a new tab)
- https://git.kernel.org/stable/c/e498b504f8c81b07efab9febf8503448de4dc9cf (opens in a new tab)
- https://git.kernel.org/stable/c/5c6f402bdcf9e7239c6bc7087eda71ac99b31379 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2021-47641)Record last updated .