Linux Kernel Btrfs free node on duplicate insert bug (CVE-2026-68450)
CVE-2026-68450 Published on August 12, 2026
btrfs: free mapping node on duplicate reloc root insert
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.
Products Associated with CVE-2026-68450
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Affected Versions
Linux:- Version 57a304cfd43b2b4a5b44b8f5dc026abb34183068 and below 92bedc0455552b42ada1a1f42b0e3a8593cdfccc is affected.
- Version 57a304cfd43b2b4a5b44b8f5dc026abb34183068 and below 14a8be9428435ee17f17fae7991215c246b7fd43 is affected.
- Version 57a304cfd43b2b4a5b44b8f5dc026abb34183068 and below 797dc567146c7e3c4f8d9680e4fbc76e0a6d9151 is affected.
- Version 57a304cfd43b2b4a5b44b8f5dc026abb34183068 and below ae0629ff9ccb836416ada129f4edc7efea6eaaad is affected.
- Version 57a304cfd43b2b4a5b44b8f5dc026abb34183068 and below 6a8269b6459ed870a8156c106a0f597383907872 is affected.
- Version 5.13 is affected.
- Before 5.13 is unaffected.
- Version 6.6.148, <= 6.6.* is unaffected.
- Version 6.12.101, <= 6.12.* is unaffected.
- Version 6.18.42, <= 6.18.* is unaffected.
- Version 7.1.6, <= 7.1.* is unaffected.
- Version 7.2-rc5, <= * is unaffected.