What’s Vulnerable › Vulnerabilities

CVE-2026-68450: btrfs: free mapping node on duplicate reloc root insert

• Severity: unknown
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-12 · updated 2026-08-19

Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: free mapping node on duplicate reloc root insert __add_reloc_root() allocates a mapping_node before inserting it into rc->reloc_root_tree. If rb_simple_insert() finds an existing entry, it returns the existing rb_node and leaves the newly allocated node unlinked. The error path then returns -EEXIST without freeing the new node. Since the node was never inserted into reloc_root_tree, the later cleanup in put_reloc_control() cannot find it either. Free the newly allocated node before returning -EEXIST. The callers currently assert that -EEXIST should not happen, so this is a defensive cleanup for an unexpected duplicate insert path. If the path is ever reached, the local allocation should still be released.

Affected products

• Linux kernel: 5.13 — fixed in 7.2

How to fix

Upgrade to a fixed version: Linux kernel 7.2. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/14a8be9428435ee17f17fae7991215c246b7fd43
• https://git.kernel.org/stable/c/29d9746812d8b7c37d594f484e994fd552c3ec33
• https://git.kernel.org/stable/c/6a8269b6459ed870a8156c106a0f597383907872
• https://git.kernel.org/stable/c/797dc567146c7e3c4f8d9680e4fbc76e0a6d9151
• https://git.kernel.org/stable/c/92bedc0455552b42ada1a1f42b0e3a8593cdfccc
• https://git.kernel.org/stable/c/ae0629ff9ccb836416ada129f4edc7efea6eaaad
• https://git.kernel.org/stable/c/b7c5b8e1d5f0779dfbabc3068b7ac0f12e53b3a8

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