CVE-2026-64177

CVE CVE-2026-64177EUVD EUVD-2026-45862Veröffentlicht 2026-07-19T15:41:01.000Z

Was das Advisory beschreibt

In the Linux kernel, the following vulnerability has been resolved: phonet/pep: disable BH around forwarded sk_receive_skb() The networking receive path is usually run from softirq context, but protocols that take the socket lock may have packets stored in the backlog and processed later from process context. In that case release_sock() -> __release_sock() drops the slock with spin_unlock_bh() and then calls sk->sk_backlog_rcv() with bottom halves enabled. Typical sk_backlog_rcv handlers process the socket whose backlog is being drained, so the BH state at entry is irrelevant for the slocks they touch. pep_do_rcv() is different: when the inbound skb targets an existing PEP pipe, it forwards the skb to a different *child* socket via sk_receive_skb(). That helper takes the child slock with bh_lock_sock_nested(), which is just spin_lock_nested() and assumes BH is already off. The same child slock therefore ends up acquired with BH on (process path) and with BH off (softirq path): process context softirq context --------------- --------------- release_sock(listener) __netif_receive_skb() __release_sock() phonet_rcv() spin_unlock_bh() __sk_receive_skb(listener) [BH now ENABLED] [BH already disabled] sk_backlog_rcv: sk_backlog_rcv: pep_do_rcv() pep_do_rcv() sk_receive_skb(child) sk_receive_skb(child) bh_lock_sock_nested(child) bh_lock_sock_nested(child) => SOFTIRQ-ON-W => IN-SOFTIRQ-W Lockdep flags this as inconsistent lock state, and it can become a real self-deadlock if a softirq on the same CPU tries to receive to the same child socket while its slock is held in the BH-enabled path: WARNING: inconsistent lock state inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. (slock-AF_PHONET/1){+.?.}-{3:3}, at: __sk_receive_skb+0x1cf/0x900 __sk_receive_skb net/core/sock.c:563 sk_receive_skb include/net/sock.h:2022 [inline] pep_do_rcv net/phonet/pep.c:675 sk_backlog_rcv include/net/sock.h:1190 __release_sock net/core/sock.c:3216 release_sock net/core/sock.c:3815 pep_sock_accept net/phonet/pep.c:879 Wrap the forwarded sk_receive_skb() in local_bh_disable() / local_bh_enable() so the child slock is always acquired with BH off. local_bh_disable() nests safely on the softirq path. Discovered via in-house syzkaller fuzzing; the same root cause also on the linux-6.1.y syzbot dashboard as extid 44f0626dd6284f02663c. Reproduced under KASAN + LOCKDEP + PROVE_LOCKING, reproducer: https://pastebin.com/A3t8xzCR

Quelle: EUVD (ENISA), im Wortlaut der Meldung.

Produkte, die das Advisory nennt

Diese Angaben stammen aus der Meldung selbst, nicht aus einer Prüfung durch uns.

• Linux — Linux 9641458d3ec42def729fde64669abf07f3220cd5 <8420aa4900417797323dd567ba9d1512280c2dc3; 9641458d3ec42def729fde64669abf07f3220cd5 <bd795f106b3889fb0706c6e4831c4b27e2b5666b; patch: 6.12.92; patch: 6.1.175; patch: 5.10.258; 9641458d3ec42def729fde64669abf07f3220cd5 <02c04df84de709060f63e1d52ec67488c4f6f212; 2.6.28; patch: 6.18.34; patch: 6.6.142; patch: 0; 9641458d3ec42def729fde64669abf07f3220cd5 <84bc87beb4cd77670939b446326788e4c9b3db37; 9641458d3ec42def729fde64669abf07f3220cd5 <b2606c302d7f2b4ee48da05e32ed60aed1b0cd53; patch: 7.1; 9641458d3ec42def729fde64669abf07f3220cd5 <f08c45076e4fd8b0adbc5eb186d6e6a3e7350d7b; 9641458d3ec42def729fde64669abf07f3220cd5 <a3fc8f2dacd1c37325977fc1fbbf3d52141df99e; patch: 7.0.11; patch: 5.15.209; 9641458d3ec42def729fde64669abf07f3220cd5 <dbc81608e3a653dea6cf403f20cae35468b8ab9c

Die genannten Versionen sind die Angabe der Meldung. Patchlage vergleicht keine Versionsnummern und leitet aus ihnen keine Aussage ab — welche Version installiert ist, muss ein Mensch nachsehen.

Im Produktkatalog geführt

Für diese Produkte kann ein Bestand in Patchlage erfasst werden. Ein Advisory dazu erscheint am Morgen danach im Lagebericht.

• Linux — Linux

Patchlage meldet Treffer und Verdachtsfälle. Zu allem anderen sagt dieses System nichts — weder diese Seite noch der Lagebericht behauptet je, dass ein Bestand sicher ist.