CVE-2026-64132

/// Technical description

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 recalcul

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References