CVE-2026-64113

In the Linux kernel, the following vulnerability has been resolved:

ixgbevf: fix use-after-free in VEPA multicast source pruning

ixgbevf_clean_rx_irq() prunes frames whose source MAC matches the VFs own address (VEPA multicast workaround) by freeing the skb and continuing to the next descriptor:

dev_kfree_skb_irq(skb);
continue;

The skb pointer is declared outside the while loop and persists across iterations. Because the continue skips the skb = NULL reset at the bottom of the loop, the next iteration enters the else if (skb) path and calls ixgbevf_add_rx_frag() on the freed skb, dereferencing skb_shinfo(skb)->nr_frags - a use-after-free in NAPI softirq context.

The sibling driver iavf already handles this correctly by nulling the pointer before continuing. Apply the same pattern here.

I do not have ixgbevf hardware; the bug was found by static analysis (scan_drop_continue_loops.py + semgrep drop_continue_in_loop, multi-tool corroboration with the highest score in the scan). The UAF was confirmed under KASAN by loading a test module that reproduces the exact code pattern (alloc skb, kfree_skb, then read skb_shinfo(skb)->nr_frags):

BUG: KASAN: slab-use-after-free in ixgbevf_uaf_test_init+0x100/0x1000 Read of size 8 at addr 000000006163ae78 by task insmod/30 freed 208-byte region [000000006163adc0, 000000006163ae90)

QEMU emulates igb (82576) but not ixgbe (82599), and the igbvf VF driver does not include the VEPA source pruning path, so a full end-to-end reproduction with emulated hardware was not possible.

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/3d931ac62411a7e43b85dba5fe45e1a4a91bd5cb
• https://git.kernel.org/stable/c/55b3e91d62b2f7a24109b2d7c9f4c66d2e3b1ec1
• https://git.kernel.org/stable/c/5d49b568c188dc77199d8d2b959c91da8cc27cf1
• https://git.kernel.org/stable/c/6ef30384a50a50e4a484cddf341bc27de31aa3de
• https://git.kernel.org/stable/c/a244395d8c563ed1bb26c3ef708db6aeeaa08084
• https://git.kernel.org/stable/c/add70e2682c0ad3be2a5810bcf1bc13963ba4df9
• https://git.kernel.org/stable/c/dfef79e09ed2f5df975c98547f97f5d7f8982a24
• https://git.kernel.org/stable/c/e8768bcbe5cd30c4ea36a22022c9ffaa66903693