SEPTEMBER 7, 2026
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Case File

CVE-2026-64113

CRITICAL · CVSS 9.8 EPSS 0.50%

Source: NVD + CISA KEV + EPSS · Published 2026-07-19 · Last synced 2026-08-18

CyberRota Analysis

AI-Generated

The vulnerability in the Linux kernel affects the ixgbevf driver, where a use-after-free condition can occur during VEPA multicast source pruning. This flaw allows an attacker to potentially exploit freed memory, leading to undefined behavior or system crashes. Organizations using affected Linux systems, particularly those relying on ixgbevf for virtual function networking, should prioritize patching this critical vulnerability to mitigate the risk of exploitation.

CVE
CVE-2026-64113
Severity
CRITICAL
CVSS
9.8
EPSS
0.50%
Linux

Original NVD Description

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 VF's 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.

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