CVE-2026-80848

Summary

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

xfrm: espintcp: fix UAF during close

ZDI reported and analyzed a race condition during close for espintcp sockets:

espintcp_close() frees emsg->skb via kfree_skb() without holding
any socket lock. Concurrently, the xfrm_trans_reinject work queue
invokes esp_output_tcp_finish() -> espintcp_push_skb() ->
espintcp_push_msgs() -> skb_send_sock_locked(), which reads the
same skb as a data source.

Fix this by adding a synchronize_rcu() call after resetting sk_prot, since esp_output_tcp_finish() runs under RCU and won't use a socket with sk_prot == &tcp_prot. Simply taking the socket lock in espintcp_close() could lead to leaks, if esp_output_tcp_finish() re-adds an skb in the slot we just freed. After this, the existing barrier() is no longer needed.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxe27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < 29121c5e6591da527e8e36ddac7120dc527f574daffected
LinuxLinuxe27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < ed5d9102190c45fc70121c036b0626b740040b75affected
LinuxLinuxe27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < 4bc0dfa28dca6fc0084203732695968049c44072affected
LinuxLinuxe27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < ff8dd7a932f34409a56e1b91a1219340f17457e9affected
LinuxLinuxe27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < 4b31a875693c480c611519faca46216514e3e052affected
LinuxLinuxe27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < 24efebecf415ba264adba0f0491cec436463a14faffected
LinuxLinuxe27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < eb3bbf29c723fe75c0eb92be14f0ec92971fe272affected
LinuxLinuxe27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < 54b41ad14da9a981131ab6e4d3f79321a503ea5daffected
LinuxLinuxe27cca96cd68fa2c6814c90f9a1cfd36bb68c593 < deb232e884877bf10b4ce2580909eedec986c284affected
LinuxLinux5.6affected
LinuxLinux0 < 5.6unaffected
LinuxLinux5.10.269 <= 5.10.*unaffected
LinuxLinux5.15.220 <= 5.15.*unaffected
LinuxLinux6.1.187 <= 6.1.*unaffected
LinuxLinux6.6.156 <= 6.6.*unaffected
LinuxLinux6.12.108 <= 6.12.*unaffected
LinuxLinux6.18.49 <= 6.18.*unaffected
LinuxLinux7.1.13 <= 7.1.*unaffected
LinuxLinux7.2.3 <= 7.2.*unaffected
LinuxLinux7.3-rc1 <= *unaffected

Weaknesses

References