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CVE Record

CVE-2024-26777: fbdev: sis: Error out if pixclock equals zero

In the Linux kernel, the following vulnerability has been resolved: fbdev: sis: Error out if pixclock equals zero The userspace program could pass any values to the driver through ioctl() interface. If the driver doesn't check the value of pixclock, it may cause divide-by-zero error. In sisfb_check_var(), var->pixclock is used as a divisor to caculate drate before it is checked against zero. Fix this by checking it at the beginning. This is similar to CVE-2022-3061 in i740fb which was fixed by commit 15cf0b8.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2024-26777 is a Linux kernel reliability flaw in the SiS framebuffer driver. A local userspace program could provide a zero pixel-clock value through an ioctl path, causing a divide-by-zero error. The business impact is mainly system instability on affected machines using this legacy graphics driver.

Executive priority

Prioritize remediation for legacy or specialized Linux endpoints where local users can access framebuffer devices. For standard servers without SiS framebuffer usage, urgency is lower but should be handled through normal kernel patch cycles.

Technical view

In sisfb_check_var(), var->pixclock was used as a divisor before checking whether it was zero. Kernel stable fixes add an early zero check. The issue is in fbdev sis handling and resembles the earlier i740fb divide-by-zero issue referenced in the CVE description.

Likely exposure

Exposure is most likely on Linux systems with the SiS fbdev driver present, enabled, and accessible to local users through framebuffer device interfaces. General server exposure may be limited, but embedded, legacy, kiosk, or specialized graphics systems should be checked.

Exploitation context

The provided sources do not show active exploitation, and the CVE is not marked KEV. The described trigger requires local userspace interaction with the driver via ioctl. Treat this as a local denial-of-service risk unless vendor guidance identifies broader impact.

Researcher notes

Evidence supports a local kernel divide-by-zero in sisfb_check_var() caused by unchecked var->pixclock. No CVSS, CWE, exploit evidence, or detailed distribution version matrix is provided in the bundle, so validation should focus on driver presence and vendor backports.

Mitigation direction

  • Update to a Linux kernel containing the referenced stable fixes.
  • Apply relevant distribution security updates, including Debian LTS advisories where applicable.
  • Disable or avoid loading the SiS framebuffer driver where not required.
  • Restrict local access to framebuffer devices using normal device permissions.
  • Check vendor kernel guidance before assuming upstream version mapping applies.

Validation and detection

  • Identify systems running kernels in the affected Linux version ranges listed by the CVE.
  • Check whether the sisfb or SiS framebuffer driver is built or loaded.
  • Confirm installed kernel includes one of the referenced stable fix commits.
  • Review distribution advisories for backported fixes in vendor kernel packages.
  • Verify framebuffer device permissions limit access to trusted local users.
Prepared
Confidence
medium
Sources
12

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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ATT&CK lookup starting points

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CVE-2024-26777 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
2ADP providers
11Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2unaffected
LinuxLinux2.6.12, 0, 4.19.308, 5.4.270, 5.10.211, 5.15.150, 6.1.80, 6.6.19, 6.7.7, 6.8affected
Weakness

CWE details

No CWE listed

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