CVE-2025-38312: Linux kernel · fbdev: core: fbcvt: avoid division by 0 in fb_cvt_hperiod()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · fixed in 5.15.0-1092.99~20.04.1 : update Linux kernel when convenient.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1092.99~20.04.1, 5.15.0-1096.105~20.04.1, 5.15.0-1092.101~20.04.1 +63
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 10 Jul 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Patches and advisories
- ubuntu.com/security/notices/USN-7769-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7770-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7771-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7769-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7774-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7774-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7774-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7775-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7776-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7769-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7775-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7775-3 (opens in a new tab)
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-aws-6.14pkg:deb/ubuntu/linux-aws-6.14?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
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.
References
- ubuntu.com/security/CVE-2025-38312 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-38312 (opens in a new tab)
- git.kernel.org/linus/3f6dae09fc8c306eb70fdfef70726e1f154e173a (opens in a new tab)
- git.kernel.org/stable/c/2d63433e8eaa3c91b2948190e395bc67009db0d9 (opens in a new tab)
- git.kernel.org/stable/c/3f6dae09fc8c306eb70fdfef70726e1f154e173a (opens in a new tab)
- git.kernel.org/stable/c/53784073cbad18f75583fd3da9ffdfc4d1f05405 (opens in a new tab)
- git.kernel.org/stable/c/54947530663edcbaaee1314c01fdd8c72861b124 (opens in a new tab)
- git.kernel.org/stable/c/610f247f2772e4f92b63442125a1b7ade79898d8 (opens in a new tab)
- git.kernel.org/stable/c/9027ce4c037b566b658b8939a76326b7125e3627 (opens in a new tab)
- git.kernel.org/stable/c/ab91647acdf43b984824776559a452212eaeb21a (opens in a new tab)
- git.kernel.org/stable/c/b235393b9f43ff86a38ca2bde6372312ea215dc5 (opens in a new tab)
- ubuntu.com/security/notices/USN-7769-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7770-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7771-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7769-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7774-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7774-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7774-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7775-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7776-1 (opens in a new tab)