CVE-2026-31452
What it is
In the Linux kernel, the following vulnerability has been resolved: ext4: convert inline data to extents when truncate exceeds inline size Add a check in ext4_setattr() to convert files from inline data storage to extent-based storage when truncate() grows the file size beyond the inline capacity. This prevents the filesystem from entering an inconsistent state where the inline data flag is set but the file size exceeds what can be stored inline. Without this fix, the following sequence causes a kernel BUG_ON(): 1. Mount filesystem with inode that has inline flag set and small size 2. truncate(file, 50MB) - grows size but inline flag remains set 3. sendfile() attempts to write data 4. ext4_write_inline_data() hits BUG_ON(write_size > inline_capacity) The crash occurs because ext4_write_inline_data() expects inline storage to accommodate the write, but the actual inline capacity (~60 bytes for i_block + ~96 bytes for xattrs) is far smaller than the file size and write request. The fix checks if the new size from setattr exceeds the inode's actual inline capacity (EXT4_I(inode)->i_inline_size) and converts the file to extent-based storage before proceeding with the size change. This addresses the root cause by ensuring the inline data flag and file size remain consistent during truncate operations.
At a glance
- Exploitability
- Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 0.1% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.1% in the next 30 days (EPSS).
- Severity: 7.8 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.1% · EPSS, next 30 days
- Weakness
- CWE-787 · Out-of-bounds write
- Record status
- Modified
Affected
- Linux Kernel < 5.10.253
- Linux Kernel < 5.15.203
- Linux Kernel < 6.1.168
- Linux Kernel < 6.6.131
- Linux Kernel < 6.12.80
- Linux Kernel < 6.18.21
- Linux Kernel < 6.19.11
- Linux Kernel 7.0
Attack profile CVSS 3.1 · 7.8
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-31452.md and follow it. Check whether this project is affected by CVE-2026-31452. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://git.kernel.org/stable/c/07c1a31af18290054da3d18221b8bf58983c5d3a
- https://git.kernel.org/stable/c/110d7ef602659ce4d7947c5480f7ca2779696aaf
- https://git.kernel.org/stable/c/699bac4d4c951974d55b045c983d1de777215949
- https://git.kernel.org/stable/c/7920dcc571cef3d8aa9ee109c136125d61d41669
- https://git.kernel.org/stable/c/93cb2d103e5c707de0f7ad58a39b7f0fddc27aa6
- https://git.kernel.org/stable/c/c047332be7195833a5c5126816c2502df8269fe4
- https://git.kernel.org/stable/c/ed9356a30e59c7cc3198e7fc46cfedf3767b9b17
- https://git.kernel.org/stable/c/f53a5d9f32924bc2a810d2df243b7714da58b636
References
- https://git.kernel.org/stable/c/07c1a31af18290054da3d18221b8bf58983c5d3a
- https://git.kernel.org/stable/c/110d7ef602659ce4d7947c5480f7ca2779696aaf
- https://git.kernel.org/stable/c/699bac4d4c951974d55b045c983d1de777215949
- https://git.kernel.org/stable/c/7920dcc571cef3d8aa9ee109c136125d61d41669
- https://git.kernel.org/stable/c/93cb2d103e5c707de0f7ad58a39b7f0fddc27aa6
- https://git.kernel.org/stable/c/c047332be7195833a5c5126816c2502df8269fe4
- https://git.kernel.org/stable/c/ed9356a30e59c7cc3198e7fc46cfedf3767b9b17
- https://git.kernel.org/stable/c/f53a5d9f32924bc2a810d2df243b7714da58b636
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-082556.html
- https://cert-portal.siemens.com/productcert/html/ssa-457936.html