Nixpkgs security tracker

Login with GitHub
⚠️ You are using a production deployment that is still only suitable for demo purposes. Any work done in this might be wiped later without notice.

Suggestion detail

Dismissed
(max. allowed matches exceeded)
Permalink CVE-2026-64044
7.8 HIGH
  • CVSS version (CVSS): 3.1
  • Attack Vector (AV): Local (L)
  • Attack Complexity (AC): Low (L)
  • Privileges Required (PR): Low (L)
  • User Interaction (UI): None (N)
  • Scope (S): Unchanged (U)
  • Confidentiality (C): High (H)
  • Integrity (I): High (H)
  • Availability (A): High (H)
  • Modified Attack Vector (MAV): Local (L)
  • Modified Attack Complexity (MAC): Low (L)
  • Modified Privileges Required (MPR): Low (L)
  • Modified User Interaction (MUI): None (N)
  • Modified Confidentiality (MC): High (H)
  • Modified Scope (MS): Unchanged (U)
  • Modified Integrity (MI): High (H)
  • Modified Availability (MA): High (H)
created 1 month, 1 week ago Activity log
  • Created & dismissed (max. allowed matches exceeded) suggestion
ovpn: respect peer refcount in CMD_NEW_PEER error path

In the Linux kernel, the following vulnerability has been resolved: ovpn: respect peer refcount in CMD_NEW_PEER error path ovpn_nl_peer_new_doit()'s error path calls ovpn_peer_release() directly rather than ovpn_peer_put(), bypassing the kref. The accompanying comment ("peer was not yet hashed, thus it is not used in any context") holds for UDP but not for TCP. For UDP, the ovpn_socket union uses the .ovpn arm and never points back at a peer; UDP encap_recv looks up peers via the not-yet-populated hashtables, so the new peer is unreachable until ovpn_peer_add() publishes it. For TCP, ovpn_socket_new() sets ovpn_sock->peer and ovpn_tcp_socket_attach() publishes ovpn_sock via rcu_assign_sk_user_data(). From that moment until ovpn_socket_release() detaches in the error path, the TCP fd is fully wired: userspace recvmsg / sendmsg / close / poll on the fd, as well as the strparser-driven ovpn_tcp_rcv() path, can reach the peer through sk_user_data -> ovpn_sock->peer and bump its refcount via ovpn_peer_hold(). ovpn_tcp_socket_wait_finish() (called inside ovpn_socket_release()) drains strparser and the tx work, but does not synchronize with userspace syscall callers that already hold a peer reference. If ovpn_nl_peer_modify() or ovpn_peer_add() returns an error while such a caller is in flight - notably an ovpn_tcp_recvmsg() blocked in __skb_recv_datagram() on peer->tcp.user_queue - the direct ovpn_peer_release() destroys the peer while the caller still holds the reference, and the eventual ovpn_peer_put() from that caller operates on freed memory. Replace the direct destructor call with ovpn_peer_put() so the kref correctly defers destruction until the last reference is dropped. In the common case where no concurrent user is present, behaviour is unchanged: the kref hits zero immediately and ovpn_peer_release_kref() runs the same destructor. With this conversion ovpn_peer_release() has no callers outside peer.c - ovpn_peer_release_kref() in the same translation unit is the only remaining user - so make it static and drop its declaration from peer.h.

Affected products

Linux
  • <1fef6614673ff0846d30acdeeaf3cf98bb5f6116
  • <0c3ef71879c0264de6c42463031d9e057da87840
  • =<*
  • <8298834912d76dbc82c12b6b4ab7590ed2bb8ae5
  • =<6.18.*
  • <6.16
  • =<7.0.*
  • ==6.16