Microsoft Security Response Center guidance
Vendor revision: Oct 20, 2026Release Notes
Vulnerability intelligence
CVE-2026-98573. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.
Release Notes
In the Linux kernel, the following vulnerability has been resolved:
net: skbuff: fix pull-bound underflow in skb_checksum_setup_ipv6()
skb_maybe_pull_tail() subtracts skb_headlen(skb) from the unsigned max argument and passes the result to __pskb_pull_tail() as a signed int. The function does not ensure that max is at least skb_headlen(skb).
This can happen while parsing IPv6 extension headers when an skb already has a linear area larger than MAX_IPV6_HDR_LEN. Once the parser needs data beyond the linear area, max - skb_headlen(skb) wraps and is converted to a negative delta. __pskb_pull_tail() then passes that negative length to skb_copy_bits(), where it can become a very large copy length.
Pass the requested length itself as the pull bound at the three extension-header call sites, so the delta can no longer go negative.
Source: NVD