Bug 2379184 (CVE-2025-38312)

Summary: CVE-2025-38312 kernel: fbdev: core: fbcvt: avoid division by 0 in fb_cvt_hperiod()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Version: unspecifiedKeywords: Security
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OS: Linux   
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Description OSIDB Bzimport 2025-07-10 08:02:15 UTC 
In the Linux kernel, the following vulnerability has been resolved:

fbdev: core: fbcvt: avoid division by 0 in fb_cvt_hperiod()

In fb_find_mode_cvt(), iff mode->refresh somehow happens to be 0x80000000,
cvt.f_refresh will become 0 when multiplying it by 2 due to overflow. It's
then passed to fb_cvt_hperiod(), where it's used as a divider -- division
by 0 will result in kernel oops. Add a sanity check for cvt.f_refresh to
avoid such overflow...

Found by Linux Verification Center (linuxtesting.org) with the Svace static
analysis tool.
Comment 1 Avinash Hanwate 2025-07-11 11:10:24 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025071015-CVE-2025-38312-8693@gregkh/T