CVE-2026-68127 ila: reload IPv6 header after pskb_may_pull in checksum adjust
Remote attackers can trigger a use-after-free in the Linux kernel ILA module via crafted IPv6 packets, potentially causing crashes or code execution.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-68127?
CVE-2026-68127 is a critical use after free vulnerability in Linux, published on 10 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ila: reload IPv6 header after pskb_may_pull in checksum adjust
ila_csum_adjust_transport() caches ip6h = ipv6_hdr(skb) before calling pskb_may_pull(). On a non-linear skb whose transport header sits in a page fragment, pskb_may_pull() can call __pskb_pull_tail() / pskb_expand_head() and free the old skb head, leaving ip6h dangling; the following get_csum_diff(ip6h, p) then reads freed memory. ila_update_ipv6_locator() uses ip6h (and the iaddr derived from it) again after the csum-adjust call and additionally writes the new locator through that pointer.
Impact: a remote IPv6 packet routed through a configured ILA csum-adjust-transport route or receive-side mapping triggers a slab-use-after-free in ila_update_ipv6_locator() (KASAN). The route or mapping requires CAP_NET_ADMIN to configure, but trigger packets are unauthenticated once it exists.
Reload ip6h after each pskb_may_pull() in ila_csum_adjust_transport() before the csum-diff read. In ila_update_ipv6_locator() only the ILA_CSUM_ADJUST_TRANSPORT case pulls the skb, so reload ip6h and iaddr in that case alone before the destination-address write; the neutral-map modes never pull and keep their cached pointers.
Weakness: CWE-416
Which versions are affected by CVE-2026-68127?
How do I fix CVE-2026-68127?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-68127 being exploited?
There is no known exploitation of CVE-2026-68127 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-68127, DEBIAN-CVE-2026-68127, GHSA-4hwh-2g43-5522, UBUNTU-CVE-2026-68127.