ext4: convert inline data to extents when truncate exceeds inline size

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Summary

CVECVE-2026-31452
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-04-22 14:16:39 UTC
Updated2026-05-06 20:12:35 UTC
DescriptionIn 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.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from [email protected]

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.000240000 probability, percentile 0.067930000 (date 2026-04-26)

Problem Types: CWE-787

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 67cf5b09a46f72e048501b84996f2f77bc42e947 110d7ef602659ce4d7947c5480f7ca2779696aaf git Not specified
CNA Linux Linux affected 67cf5b09a46f72e048501b84996f2f77bc42e947 f53a5d9f32924bc2a810d2df243b7714da58b636 git Not specified
CNA Linux Linux affected 67cf5b09a46f72e048501b84996f2f77bc42e947 c047332be7195833a5c5126816c2502df8269fe4 git Not specified
CNA Linux Linux affected 67cf5b09a46f72e048501b84996f2f77bc42e947 699bac4d4c951974d55b045c983d1de777215949 git Not specified
CNA Linux Linux affected 67cf5b09a46f72e048501b84996f2f77bc42e947 7920dcc571cef3d8aa9ee109c136125d61d41669 git Not specified
CNA Linux Linux affected 67cf5b09a46f72e048501b84996f2f77bc42e947 93cb2d103e5c707de0f7ad58a39b7f0fddc27aa6 git Not specified
CNA Linux Linux affected 67cf5b09a46f72e048501b84996f2f77bc42e947 07c1a31af18290054da3d18221b8bf58983c5d3a git Not specified
CNA Linux Linux affected 67cf5b09a46f72e048501b84996f2f77bc42e947 ed9356a30e59c7cc3198e7fc46cfedf3767b9b17 git Not specified
CNA Linux Linux affected 3.8 Not specified
CNA Linux Linux unaffected 3.8 semver Not specified
CNA Linux Linux unaffected 5.10.253 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.203 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.168 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.131 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.80 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.21 6.18.* semver Not specified
CNA Linux Linux unaffected 6.19.11 6.19.* semver Not specified
CNA Linux Linux unaffected 7.0 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/699bac4d4c951974d55b045c983d1de777215949 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/110d7ef602659ce4d7947c5480f7ca2779696aaf 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/f53a5d9f32924bc2a810d2df243b7714da58b636 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/93cb2d103e5c707de0f7ad58a39b7f0fddc27aa6 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/07c1a31af18290054da3d18221b8bf58983c5d3a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/ed9356a30e59c7cc3198e7fc46cfedf3767b9b17 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/7920dcc571cef3d8aa9ee109c136125d61d41669 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/c047332be7195833a5c5126816c2502df8269fe4 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
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