CVE-2026-98241

Summary

In the Linux kernel, the following vulnerability has been resolved:

ipv6: xfrm: use full sockets in local error paths

xfrm6_local_rxpmtu() and xfrm6_local_error() dereference skb->sk as if it always pointed at a full IPv6 socket.

That is not guaranteed. TCP SYN-ACK skbs can be owned by a TCP_NEW_SYN_RECV request_sock while the output path itself is driven by the full listener. If rerouting selects an IPv6 XFRM tunnel route with a lower MTU, the local PMTU/error handling path can reach these callbacks with that mini-socket still attached to the skb.

The callbacks then miscast the request socket as a full inet/IPv6 socket and can read beyond the request_sock allocation when they access inet_sock or ipv6_pinfo state.

Resolve the owner with skb_to_full_sk() in both callbacks and bail out when no full socket is attached. This matches the surrounding XFRM IPv6 PMTU/error logic, which already reasons about full sockets with skb_to_full_sk().

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxdd767856a36e00b631d65ebc4bb81b19915532d6 < b1a88633c36d2cbc3831382f3846754d344276fdaffected
LinuxLinuxdd767856a36e00b631d65ebc4bb81b19915532d6 < 904a0e827d0d7189271a3a2eb648293809f25efcaffected
LinuxLinuxdd767856a36e00b631d65ebc4bb81b19915532d6 < 675919e08ce266b8cac11fd9af29170e762a480faffected
LinuxLinuxdd767856a36e00b631d65ebc4bb81b19915532d6 < 60459c670329d586a58db5d8f811fa5accfe4862affected
LinuxLinuxdd767856a36e00b631d65ebc4bb81b19915532d6 < ca3d68c3213475b53db6647e159dc73bd1af5ab1affected
LinuxLinuxdd767856a36e00b631d65ebc4bb81b19915532d6 < 4c030a0400ebfd2318361c923a88103b2c67c49faffected
LinuxLinuxdd767856a36e00b631d65ebc4bb81b19915532d6 < c21f3f7fbfeda7c5794f606cb0ffcc2d9001eef8affected
LinuxLinuxdd767856a36e00b631d65ebc4bb81b19915532d6 < 6973a21ee73c5567f883813c8ef414774b45892faffected
LinuxLinux3.2affected
LinuxLinux0 < 3.2unaffected
LinuxLinux5.10.271 <= 5.10.*unaffected
LinuxLinux5.15.222 <= 5.15.*unaffected
LinuxLinux6.1.189 <= 6.1.*unaffected
LinuxLinux6.6.158 <= 6.6.*unaffected
LinuxLinux6.12.112 <= 6.12.*unaffected
LinuxLinux6.18.54 <= 6.18.*unaffected
LinuxLinux7.2.8 <= 7.2.*unaffected
LinuxLinux7.3-rc4 <= *unaffected

Weaknesses

References