CVE-2026-31429

The record

In the Linux kernel, the following vulnerability has been resolved: net: skb: fix cross-cache free of KFENCE-allocated skb head SKB_SMALL_HEAD_CACHE_SIZE is intentionally set to a non-power-of-2 value (e.g. 704 on x86_64) to avoid collisions with generic kmalloc bucket sizes. This ensures that skb_kfree_head() can reliably use skb_end_offset to distinguish skb heads allocated from skb_small_head_cache vs. generic kmalloc caches. However, when KFENCE is enabled, kfence_ksize() returns the exact requested allocation size instead of the slab bucket size. If a caller (e.g. bpf_test_init) allocates skb head data via kzalloc() and the requested size happens to equal SKB_SMALL_HEAD_CACHE_SIZE, then slab_build_skb() -> ksize() returns that exact value. After subtracting skb_shared_info overhead, skb_end_offset ends up matching SKB_SMALL_HEAD_HEADROOM, causing skb_kfree_head() to incorrectly free the object to skb_small_head_cache instead of back to the original kmalloc cache, resulting in a slab cross-cache free: kmem_cache_free(skbuff_small_head): Wrong slab cache. Expected skbuff_small_head but got kmalloc-1k Fix this by always calling kfree(head) in skb_kfree_head(). This keeps the free path generic and avoids allocator-specific misclassification for KFENCE objects.

Affected packages

Related vulnerabilities

• CVE-2026-109278 ImageMagick before 6.9.13-57 and 7.x before 7.1.2-32 contains a memory leak in the… CWE-401
• CVE-2026-109270 ImageMagick before 7.1.2-32 contains a memory leak vulnerability in the -process option… CWE-401
• CVE-2026-109262 ImageMagick before 6.9.13-57 and 7.x before 7.1.2-32 contains a memory leak in the SVG… CWE-401
• CVE-2026-109263 ImageMagick before 6.9.13-57 and 7.x before 7.1.2-32 contains a memory leak in the YUV… CWE-401
• CVE-2026-109261 ImageMagick before 6.9.13-57 and 7.x before 7.1.2-32 contains a memory leak in the GIF… CWE-401
• CVE-2026-109260 ImageMagick before 6.9.13-57 and 7.x before 7.1.2-32 contains a memory leak in the PNG… CWE-401
• CVE-2026-104874 Multidict is an implementation of a multidict data structure. CWE-401
• CVE-2026-98162 In the Linux kernel, the following vulnerability has been resolved: smb/server: fix tree… CWE-401