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Linux Kernel IPv6 xfrm Error Path Casts request_sock as a Full Socket, Triggering a Local Use-After-Free

Last refreshed2026-10-10

Status: UPDATED  |  Advisory ID: CVE-2026-98241

Key Details

CVECVE-2026-98241
CVSS Score / Version7.8 (High) / CVSS v3.1
Updated2026-10-07
CVSS VectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS Proseattack vector is local; attack complexity is low; privileges required is low; user interaction is none; scope is unchanged; confidentiality impact is high; integrity impact is high; availability impact is high.
Affected productsLinux Kernel

Affected Products, Subsystems & Sectors

VendorProductAffected VersionsPatch Status
LinuxLinux Kernel
SubsystemsOT Supporting Infrastructure
SectorsAll Sectors

What to Know

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(). (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References

SourceReference
NVDhttps://nvd.nist.gov/vuln/detail/CVE-2026-98241
CVEhttps://www.cve.org/CVERecord?id=CVE-2026-98241