CVE-2021-47641: video: fbdev: cirrusfb: check pixclock to avoid divide by zero
Noroxi assessment
Priority: Monitor (action score 22/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.25% (FIRST EPSS).
- Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
- Fixed version: Linux Linux 1d3fb46439ad4e8f0c5739eb33d1875ac9e0f135, 40b13e3d85744210db13457785646634e2d056bd, 45800c42ef000f417270bcfc08630e42486fca99.
Low priority for now. Upgrade to Linux Linux 1d3fb46439ad4e8f0c5739eb33d1875ac9e0f135, 40b13e3d85744210db13457785646634e2d056bd, 45800c42ef000f417270bcfc08630e42486fca99 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
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
- Published
- Feb 26, 2025
- Updated
- Jun 17, 2026
- EPSS
- 0.2% · 15th percentile
- CWE
- CWE-369
Report tools
Action score
22
Monitor
Low priority for now.
- CVSS
- 22 / 40 · 5.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.2%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| linux | linux kernel | cpe:2.3:o:linux:linux_kernel |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- linux linux kernelbefore 4.9.311
- linux linux kernel4.10 and later · before 4.14.276
- linux linux kernel4.15 and later · before 4.19.238
- linux linux kernel4.20 and later · before 5.4.189
- linux linux kernel5.5 and later · before 5.10.110
- linux linux kernel5.11 and later · before 5.15.33
- linux linux kernel5.16 and later · before 5.16.19
- linux linux kernel5.17 and later · before 5.17.2
Versions reported by the vendor
Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.
Linux Linux
- 2.6.12affected
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before c656d04247a2654ede5cead2ecbf83431dad5261affected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 1d3fb46439ad4e8f0c5739eb33d1875ac9e0f135affected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 40b13e3d85744210db13457785646634e2d056bdaffected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 53a2088a396cfa1da92690a1da289634cd73bf0daffected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 8c7e2141fb89c620ab4e41512e262fbf25b8260daffected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 6fe23ff94e7840097202e85c148688940b37c9b1affected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 45800c42ef000f417270bcfc08630e42486fca99affected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before e498b504f8c81b07efab9febf8503448de4dc9cfaffected · git
- 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 5c6f402bdcf9e7239c6bc7087eda71ac99b31379affected · git
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | linux | before 5.17.3-1 | 5.17.3-1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-64kb | before 5.3.18-150300.59.201.1 | 5.3.18-150300.59.201.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-default-base | before 5.3.18-150300.59.201.1.150300.18.120.1 | 5.3.18-150300.59.201.1.150300.18.120.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-docs | before 5.3.18-150300.59.201.1 | 5.3.18-150300.59.201.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-obs-build | before 5.3.18-150300.59.201.1 | 5.3.18-150300.59.201.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-preempt | before 5.3.18-150300.59.201.1 | 5.3.18-150300.59.201.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-source | before 5.3.18-150300.59.201.1 | 5.3.18-150300.59.201.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | kernel-syms | before 5.3.18-150300.59.201.1 | 5.3.18-150300.59.201.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | kernel-64kb | before 5.14.21-150400.24.158.1 | 5.14.21-150400.24.158.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | kernel-docs | before 5.14.21-150400.24.158.1 | 5.14.21-150400.24.158.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | kernel-obs-build | before 5.14.21-150400.24.158.1 | 5.14.21-150400.24.158.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | kernel-source | before 5.14.21-150400.24.158.1 | 5.14.21-150400.24.158.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | kernel-syms | before 5.14.21-150400.24.158.1 | 5.14.21-150400.24.158.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS | kernel-64kb | before 5.14.21-150500.55.100.1 | 5.14.21-150500.55.100.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS | kernel-docs | before 5.14.21-150500.55.100.1 | 5.14.21-150500.55.100.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS | kernel-obs-build | before 5.14.21-150500.55.100.1 | 5.14.21-150500.55.100.1 |
| SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS | kernel-syms | before 5.14.21-150500.55.100.1 | 5.14.21-150500.55.100.1 |
| SUSE:Linux Enterprise Live Patching 15 SP3 | kernel-default | before 5.3.18-150300.59.201.1 | 5.3.18-150300.59.201.1 |
| SUSE:Linux Enterprise Live Patching 15 SP3 | kernel-livepatch-SLE15-SP3_Update_56 | before 1-150300.7.3.1 | 1-150300.7.3.1 |
| SUSE:Linux Enterprise Live Patching 15 SP4 | kernel-livepatch-SLE15-SP4_Update_38 | before 1-150400.9.3.1 | 1-150400.9.3.1 |
| SUSE:Linux Enterprise Live Patching 15 SP5 | kernel-livepatch-SLE15-SP5_Update_25 | before 1-150500.11.3.1 | 1-150500.11.3.1 |
| SUSE:Linux Enterprise Micro 5.1 | kernel-rt | before 5.3.18-150300.205.1 | 5.3.18-150300.205.1 |
| SUSE:Linux Enterprise Micro 5.1 | kernel-source-rt | before 5.3.18-150300.205.1 | 5.3.18-150300.205.1 |
| SUSE:Linux Enterprise Micro 5.3 | kernel-default | before 5.14.21-150400.24.158.1 | 5.14.21-150400.24.158.1 |
+11
Same product
linux: all recordsOther highest-scoring records for the same primary product.
- CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV89Now
- CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV85Now
- CVE-2016-5195Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by leveraging incorrect haKEV83Now
Published before and after this one in the same product
- ← EarlierCVE-2021-47639Feb 26, 2025 · KVM: x86/mmu: Zap _all_ roots when unmapping gfn range in TDP MMU31Monitor
- ← EarlierCVE-2021-47640Feb 26, 2025 · powerpc/kasan: Fix early region not updated correctly31Monitor
- Later →CVE-2021-47642Feb 26, 2025 · video: fbdev: nvidiafb: Use strscpy() to prevent buffer overflow31Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Linux Linux | 1d3fb46439ad4e8f0c5739eb33d1875ac9e0f135 | Vendor (CNA) |
| Linux Linux | 40b13e3d85744210db13457785646634e2d056bd | Vendor (CNA) |
| Linux Linux | 45800c42ef000f417270bcfc08630e42486fca99 | Vendor (CNA) |
| Linux Linux | 53a2088a396cfa1da92690a1da289634cd73bf0d | Vendor (CNA) |
| Linux Linux | 5c6f402bdcf9e7239c6bc7087eda71ac99b31379 | Vendor (CNA) |
| Linux Linux | 6fe23ff94e7840097202e85c148688940b37c9b1 | Vendor (CNA) |
| Linux Linux | 8c7e2141fb89c620ab4e41512e262fbf25b8260d | Vendor (CNA) |
| Linux Linux | c656d04247a2654ede5cead2ecbf83431dad5261 | Vendor (CNA) |
| Linux Linux | e498b504f8c81b07efab9febf8503448de4dc9cf | Vendor (CNA) |
| debian:linux | 5.17.3-1 · Debian:12 | Package registry (OSV) |
| suse:kernel-64kb | 5.14.21-150400.24.158.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | Package registry (OSV) |
| suse:kernel-default | 5.14.21-150400.24.158.1 · SUSE:Linux Enterprise Micro 5.3 | Package registry (OSV) |
| suse:kernel-default-base | 5.14.21-150400.24.158.1.150400.24.78.1 · SUSE:Linux Enterprise Micro 5.3 | Package registry (OSV) |
| suse:kernel-docs | 5.14.21-150400.24.158.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | Package registry (OSV) |
| suse:kernel-livepatch-SLE15-SP4_Update_38 | 1-150400.9.3.1 · SUSE:Linux Enterprise Live Patching 15 SP4 | Package registry (OSV) |
| suse:kernel-livepatch-SLE15-SP5_Update_25 | 1-150500.11.3.1 · SUSE:Linux Enterprise Live Patching 15 SP5 | Package registry (OSV) |
| suse:kernel-obs-build | 5.14.21-150400.24.158.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | Package registry (OSV) |
| suse:kernel-rt | 5.14.21-150500.13.91.1 · SUSE:Linux Enterprise Micro 5.5 | Package registry (OSV) |
| suse:kernel-source | 5.14.21-150400.24.158.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | Package registry (OSV) |
| suse:kernel-source-rt | 5.14.21-150500.13.91.1 · SUSE:Linux Enterprise Micro 5.5 | Package registry (OSV) |
| suse:kernel-syms | 5.14.21-150400.24.158.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOS | Package registry (OSV) |
| suse:kernel-zfcpdump | 5.14.21-150400.24.158.1 · SUSE:Linux Enterprise Server 15 SP4-LTSS | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2024-26945301 days apartcrypto: iaa - Fix nr_cpus < nr_iaa case33Monitor
- CVE-2022-492940 days apartdrm/amd/display: Check if modulo is 0 before dividing.22Monitor
- CVE-2022-493300 days aparttcp: fix tcp_mtup_probe_success vs wrong snd_cwnd22Monitor
- CVE-2022-496700 days apartlinux/dim: Fix divide by 0 in RDMA DIM22Monitor
- CVE-2025-217930 days apartspi: sn-f-ospi: Fix division by zero22Monitor
- CVE-2024-5795016 days apartdrm/amd/display: Initialize denominator defaults to 122Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-369 · Divide By ZeroCVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (8 more)Show less
- git.kernel.org/stable/c/40b13e3d85744210db13457785646634e2d056bd
- git.kernel.org/stable/c/45800c42ef000f417270bcfc08630e42486fca99
- git.kernel.org/stable/c/53a2088a396cfa1da92690a1da289634cd73bf0d
- git.kernel.org/stable/c/5c6f402bdcf9e7239c6bc7087eda71ac99b31379
- git.kernel.org/stable/c/6fe23ff94e7840097202e85c148688940b37c9b1
- git.kernel.org/stable/c/8c7e2141fb89c620ab4e41512e262fbf25b8260d
- git.kernel.org/stable/c/c656d04247a2654ede5cead2ecbf83431dad5261
- git.kernel.org/stable/c/e498b504f8c81b07efab9febf8503448de4dc9cf
Vendor advisories and official records. Exploit/PoC links are deliberately left out.