CVE-2026-31412: Linux kernel · usb: gadget: f_mass_storage: Fix potential integer overflow in
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 5.5 Medium · patch available : update Linux kernel when convenient.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available
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 Apr 2026
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
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 25.10linuxpkg:deb/ubuntu/linux@6.17.0-40.40?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws@6.17.0-1019.19?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure@6.17.0-1020.20?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde@6.17.0-1017.17?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp@6.17.0-1020.22?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle@6.17.0-1018.18?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch is available and included in Linux kernel versions 6.8.0-1061.64~22.04.1 and later. Users should update their Linux kernel to these fixed versions or later and reboot the system to apply the changes. Due to an ABI change, recompilation and reinstallation of third-party kernel modules may be necessary. Follow vendor advisories for detailed update instructions.
Description
In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_mass_storage: Fix potential integer overflow in check_command_size_in_blocks() The `check_command_size_in_blocks()` function calculates the data size in bytes by left shifting `common->data_size_from_cmnd` by the block size (`common->curlun->blkbits`). However, it does not validate whether this shift operation will cause an integer overflow. Initially, the block size is set up in `fsg_lun_open()` , and the `common->data_size_from_cmnd` is set up in `do_scsi_command()`. During initialization, there is no integer overflow check for the interaction between two variables. So if a malicious USB host sends a SCSI READ or WRITE command requesting a large amount of data (`common->data_size_from_cmnd`), the left shift operation can wrap around. This results in a truncated data size, which can bypass boundary checks and potentially lead to memory corruption or out-of-bounds accesses. Fix this by using the check_shl_overflow() macro to safely perform the shift and catch any overflows.
References
- ubuntu.com/security/CVE-2026-31412 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-31412 (opens in a new tab)
- git.kernel.org/linus/8479891d1f04a8ce55366fe4ca361ccdb96f02e1 (opens in a new tab)
- git.kernel.org/stable/c/228b37936376143f4b60cc6828663f6eaceb81b5 (opens in a new tab)
- git.kernel.org/stable/c/3428dc5520c811e66622b2f5fa43341bf9a1f8b3 (opens in a new tab)
- git.kernel.org/stable/c/387ebb0453b99d71491419a5dc4ab4bee0cacbac (opens in a new tab)
- git.kernel.org/stable/c/8479891d1f04a8ce55366fe4ca361ccdb96f02e1 (opens in a new tab)
- git.kernel.org/stable/c/91817ad5452defe69bc7bc0e355f0ed5d01125cc (opens in a new tab)
- git.kernel.org/stable/c/ce0caaed5940162780c5c223b8ae54968a5f059b (opens in a new tab)
- ubuntu.com/security/notices/USN-8567-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8574-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8574-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8595-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8596-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8595-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8606-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8607-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8608-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8609-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8574-3 (opens in a new tab)