hugetlbfs: fix null-ptr-deref in hugetlbfs_parse_param()

Description

In the Linux kernel, the following vulnerability has been resolved: hugetlbfs: fix null-ptr-deref in hugetlbfs_parse_param() Syzkaller reports a null-ptr-deref bug as follows: ====================================================== KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: 0010:hugetlbfs_parse_param+0x1dd/0x8e0 fs/hugetlbfs/inode.c:1380 [...] Call Trace: <TASK> vfs_parse_fs_param fs/fs_context.c:148 [inline] vfs_parse_fs_param+0x1f9/0x3c0 fs/fs_context.c:129 vfs_parse_fs_string+0xdb/0x170 fs/fs_context.c:191 generic_parse_monolithic+0x16f/0x1f0 fs/fs_context.c:231 do_new_mount fs/namespace.c:3036 [inline] path_mount+0x12de/0x1e20 fs/namespace.c:3370 do_mount fs/namespace.c:3383 [inline] __do_sys_mount fs/namespace.c:3591 [inline] __se_sys_mount fs/namespace.c:3568 [inline] __x64_sys_mount+0x27f/0x300 fs/namespace.c:3568 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd [...] </TASK> ====================================================== According to commit "vfs: parse: deal with zero length string value", kernel will set the param->string to null pointer in vfs_parse_fs_string() if fs string has zero length. Yet the problem is that, hugetlbfs_parse_param() will dereference the param->string, without checking whether it is a null pointer. To be more specific, if hugetlbfs_parse_param() parses an illegal mount parameter, such as "size=,", kernel will constructs struct fs_parameter with null pointer in vfs_parse_fs_string(), then passes this struct fs_parameter to hugetlbfs_parse_param(), which triggers the above null-ptr-deref bug. This patch solves it by adding sanity check on param->string in hugetlbfs_parse_param().

Scores

EPSS (exploitation in 30 days)

0.16% · top 95% of all CVEs (6 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.5.

Weakness

• CWE-476 (opens in a new tab)All about CWE-476 and its CVEs

Affected products

• Linux · Linux

  • affected 32021982a324dce93b4ae00c06213bf45fb319c8 – < fa71639873518e3587632ae58e25e4a96b57fa90
  • affected 32021982a324dce93b4ae00c06213bf45fb319c8 – < dcd28191be9bbf307ba51a5b485773a55b0037c4
  • affected 32021982a324dce93b4ae00c06213bf45fb319c8 – < 9a8862820cbf1f18dca4f3b4c289d88561b3a384
  • affected 32021982a324dce93b4ae00c06213bf45fb319c8 – < 965e8f8ae0f642b5528f5a82b7bcaf15a659d5bd
  • affected 32021982a324dce93b4ae00c06213bf45fb319c8 – < f2207145693ae5697a7b59e2add4b92f9e5b0e3c
  • affected 32021982a324dce93b4ae00c06213bf45fb319c8 – < 26215b7ee923b9251f7bb12c4e5f09dc465d35f2

• Linux · Linux

  • affected 5.1
  • unaffected < 5.1
  • unaffected 5.4.229 – ≤ 5.4.*
  • unaffected 5.10.163 – ≤ 5.10.*
  • unaffected 5.15.86 – ≤ 5.15.*
  • unaffected 6.0.16 – ≤ 6.0.*
  • unaffected 6.1.2 – ≤ 6.1.*
  • unaffected 6.2 – ≤ *

References (6)

• https://git.kernel.org/stable/c/fa71639873518e3587632ae58e25e4a96b57fa90 (opens in a new tab)
• https://git.kernel.org/stable/c/dcd28191be9bbf307ba51a5b485773a55b0037c4 (opens in a new tab)
• https://git.kernel.org/stable/c/9a8862820cbf1f18dca4f3b4c289d88561b3a384 (opens in a new tab)
• https://git.kernel.org/stable/c/965e8f8ae0f642b5528f5a82b7bcaf15a659d5bd (opens in a new tab)
• https://git.kernel.org/stable/c/f2207145693ae5697a7b59e2add4b92f9e5b0e3c (opens in a new tab)
• https://git.kernel.org/stable/c/26215b7ee923b9251f7bb12c4e5f09dc465d35f2 (opens in a new tab)

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2022-50334](https://trackcve.app/badge/CVE-2022-50334.svg)](https://trackcve.app/cve/CVE-2022-50334)

Record last updated 5 Nov 2026, 20:10 UTC.