Bug 2424986 (CVE-2023-54033)

Summary: CVE-2023-54033 kernel: bpf: fix a memory leak in the LRU and LRU_PERCPU hash maps
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Version: unspecifiedKeywords: Security
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OS: Linux   
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Description OSIDB Bzimport 2025-12-24 12:06:06 UTC 
In the Linux kernel, the following vulnerability has been resolved:

bpf: fix a memory leak in the LRU and LRU_PERCPU hash maps

The LRU and LRU_PERCPU maps allocate a new element on update before locking the
target hash table bucket. Right after that the maps try to lock the bucket.
If this fails, then maps return -EBUSY to the caller without releasing the
allocated element. This makes the element untracked: it doesn't belong to
either of free lists, and it doesn't belong to the hash table, so can't be
re-used; this eventually leads to the permanent -ENOMEM on LRU map updates,
which is unexpected. Fix this by returning the element to the local free list
if bucket locking fails.
Comment 1 Alexander B 2025-12-25 10:51:11 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025122437-CVE-2023-54033-ad11@gregkh/T