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CVE-2021-47641· NVD / CVE Program· CNA Linux

video: fbdev: cirrusfb: check pixclock to avoid divide by zero

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

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Feb 26, 2025
Updated
Jun 17, 2026
EPSS
0.3% · 15th percentile
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JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Affected systems

VendorProduct
linuxlinux 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.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 5.17.3-15.17.3-1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSkernel-64kbbefore 5.3.18-150300.59.201.15.3.18-150300.59.201.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSkernel-default-basebefore 5.3.18-150300.59.201.1.150300.18.120.15.3.18-150300.59.201.1.150300.18.120.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSkernel-docsbefore 5.3.18-150300.59.201.15.3.18-150300.59.201.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSkernel-obs-buildbefore 5.3.18-150300.59.201.15.3.18-150300.59.201.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSkernel-preemptbefore 5.3.18-150300.59.201.15.3.18-150300.59.201.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSkernel-sourcebefore 5.3.18-150300.59.201.15.3.18-150300.59.201.1
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSSkernel-symsbefore 5.3.18-150300.59.201.15.3.18-150300.59.201.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSkernel-64kbbefore 5.14.21-150400.24.158.15.14.21-150400.24.158.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSkernel-docsbefore 5.14.21-150400.24.158.15.14.21-150400.24.158.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSkernel-obs-buildbefore 5.14.21-150400.24.158.15.14.21-150400.24.158.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSkernel-sourcebefore 5.14.21-150400.24.158.15.14.21-150400.24.158.1
SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSkernel-symsbefore 5.14.21-150400.24.158.15.14.21-150400.24.158.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOSkernel-64kbbefore 5.14.21-150500.55.100.15.14.21-150500.55.100.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOSkernel-docsbefore 5.14.21-150500.55.100.15.14.21-150500.55.100.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOSkernel-obs-buildbefore 5.14.21-150500.55.100.15.14.21-150500.55.100.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOSkernel-symsbefore 5.14.21-150500.55.100.15.14.21-150500.55.100.1
SUSE:Linux Enterprise Live Patching 15 SP3kernel-defaultbefore 5.3.18-150300.59.201.15.3.18-150300.59.201.1
SUSE:Linux Enterprise Live Patching 15 SP3kernel-livepatch-SLE15-SP3_Update_56before 1-150300.7.3.11-150300.7.3.1
SUSE:Linux Enterprise Live Patching 15 SP4kernel-livepatch-SLE15-SP4_Update_38before 1-150400.9.3.11-150400.9.3.1
SUSE:Linux Enterprise Live Patching 15 SP5kernel-livepatch-SLE15-SP5_Update_25before 1-150500.11.3.11-150500.11.3.1
SUSE:Linux Enterprise Micro 5.1kernel-rtbefore 5.3.18-150300.205.15.3.18-150300.205.1
SUSE:Linux Enterprise Micro 5.1kernel-source-rtbefore 5.3.18-150300.205.15.3.18-150300.205.1
SUSE:Linux Enterprise Micro 5.3kernel-defaultbefore 5.14.21-150400.24.158.15.14.21-150400.24.158.1

+11

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  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now
  • 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 haKEV
    83Now
  • CVE-2019-13272In the Linux kernel before 5.1.17, ptrace_link in kernel/ptrace.c mishandles the recording of the credentials of a process that wants to creKEV
    77This week
  • CVE-2013-6282The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the v6k and v7 ARM platforms do not validate certain addKEV
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  • CVE-2013-2094The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9 uses an incorrect integer data type, which allows loKEV
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Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux1d3fb46439ad4e8f0c5739eb33d1875ac9e0f135Vendor (CNA)
Linux Linux40b13e3d85744210db13457785646634e2d056bdVendor (CNA)
Linux Linux45800c42ef000f417270bcfc08630e42486fca99Vendor (CNA)
Linux Linux53a2088a396cfa1da92690a1da289634cd73bf0dVendor (CNA)
Linux Linux5c6f402bdcf9e7239c6bc7087eda71ac99b31379Vendor (CNA)
Linux Linux6fe23ff94e7840097202e85c148688940b37c9b1Vendor (CNA)
Linux Linux8c7e2141fb89c620ab4e41512e262fbf25b8260dVendor (CNA)
Linux Linuxc656d04247a2654ede5cead2ecbf83431dad5261Vendor (CNA)
Linux Linuxe498b504f8c81b07efab9febf8503448de4dc9cfVendor (CNA)
debian:linux5.17.3-1 · Debian:12Package registry (OSV)
suse:kernel-64kb5.14.21-150400.24.158.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSPackage registry (OSV)
suse:kernel-default5.14.21-150400.24.158.1 · SUSE:Linux Enterprise Micro 5.3Package registry (OSV)
suse:kernel-default-base5.14.21-150400.24.158.1.150400.24.78.1 · SUSE:Linux Enterprise Micro 5.3Package registry (OSV)
suse:kernel-docs5.14.21-150400.24.158.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSPackage registry (OSV)
suse:kernel-livepatch-SLE15-SP4_Update_381-150400.9.3.1 · SUSE:Linux Enterprise Live Patching 15 SP4Package registry (OSV)
suse:kernel-livepatch-SLE15-SP5_Update_251-150500.11.3.1 · SUSE:Linux Enterprise Live Patching 15 SP5Package registry (OSV)
suse:kernel-obs-build5.14.21-150400.24.158.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSPackage registry (OSV)
suse:kernel-rt5.14.21-150500.13.91.1 · SUSE:Linux Enterprise Micro 5.5Package registry (OSV)
suse:kernel-source5.14.21-150400.24.158.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSPackage registry (OSV)
suse:kernel-source-rt5.14.21-150500.13.91.1 · SUSE:Linux Enterprise Micro 5.5Package registry (OSV)
suse:kernel-syms5.14.21-150400.24.158.1 · SUSE:Linux Enterprise High Performance Computing 15 SP4-ESPOSPackage registry (OSV)
suse:kernel-zfcpdump5.14.21-150400.24.158.1 · SUSE:Linux Enterprise Server 15 SP4-LTSSPackage 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.

EPSS, last 120 days

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.

Finders, 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 case
    33Monitor
  • 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_cwnd
    22Monitor
  • CVE-2022-496700 days apartlinux/dim: Fix divide by 0 in RDMA DIM
    22Monitor
  • CVE-2025-217930 days apartspi: sn-f-ospi: Fix division by zero
    22Monitor
  • CVE-2024-5795016 days apartdrm/amd/display: Initialize denominator defaults to 1
    22Monitor

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 Zero

CVSS 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.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

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Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

All records