CVE-2026-64132
CriticalCVSS 9.8Exploitation Probability (EPSS)
Low risk39th percentile - higher than 39% of all known CVEs
Summary
A vulnerability was found in the Linux kernel's IOAM implementation for IPv6. The ipv6_hop_ioam() function fails to refresh the hdr pointer after a potential data buffer reallocation by skb_ensure_writable(), leading to a Use-After-Free condition.
Risk Assessment
An attacker could exploit this vulnerability to gain unauthorized access to kernel memory, potentially leading to privilege escalation or sensitive data leakage.
Recommendation
Immediately update the Linux kernel to a version containing the fix (commit that refreshes the hdr pointer before calling ioam6_event()).
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: ipv6: ioam: refresh hdr pointer before ioam6_event() Reported by Sashiko: In ipv6_hop_ioam(), the hdr pointer is initialized to point into the skb's linear data buffer. Later, the code calls skb_ensure_writable(), which might reallocate the buffer: if (skb_ensure_writable(skb, optoff + 2 + hdr->opt_len)) goto drop; /* Trace pointer may have changed */ trace = (struct ioam6_trace_hdr *)(skb_network_header(skb) + optoff + sizeof(*hdr)); ioam6_fill_trace_data(skb, ns, trace, true); ioam6_event(IOAM6_EVENT_TRACE, dev_net(skb->dev), GFP_ATOMIC, (void *)trace, hdr->opt_len - 2); If the skb is cloned or lacks sufficient linear headroom, skb_ensure_writable() will invoke pskb_expand_head(), which reallocates the skb's data buffer and frees the old one, invalidating pointers to it. While the code recalculates the trace pointer immediately after the call to skb_ensure_writable(), it fails to recalculate the hdr pointer. This patch fixes the above by recalculating the hdr pointer before passing hdr->opt_len to ioam6_event(), so that we avoid any UaF.