CVE-2026-64401

CVE CVE-2026-64401EUVD EUVD-2026-48945Veröffentlicht 2026-07-25T08:50:44.000ZZuletzt geändert 2026-08-05T12:41:39.000ZCVSS 7.8

Was das Advisory beschreibt

In the Linux kernel, the following vulnerability has been resolved: smb: client: resolve SWN tcon from live registrations cifs_swn_notify() looks up a witness registration by id under cifs_swnreg_idr_mutex, drops the mutex, and then uses the registration's cached tcon pointer. That pointer is not a lifetime reference, and it is not a stable representative once cifs_get_swn_reg() lets multiple tcons for the same net/share name share one registration id. A same-share second mount can keep the cifs_swn_reg alive after the first tcon unregisters and is freed. The registration then still points at the freed first tcon, so taking tc_lock or incrementing tc_count through swnreg->tcon only moves the use-after-free earlier. Taking tc_lock while holding cifs_swnreg_idr_mutex also violates the documented CIFS lock order. Fix this by making the registration store only the stable witness identity: id, net name, share name, and notify flags. When a notify arrives, copy that identity under cifs_swnreg_idr_mutex, drop the mutex, then find and pin a live witness tcon that currently matches the net/share pair under the normal cifs_tcp_ses_lock -> tc_lock order. The notification path uses that pinned tcon directly and drops the reference when done. Registration and unregister messages now use the live tcon passed by the caller instead of a cached tcon in the registration. The final unregister send is folded into cifs_swn_unregister() while the registration is still protected by cifs_swnreg_idr_mutex. This removes the previous find/drop/reacquire raw-pointer window. The release path only removes the idr entry and frees the stable identity strings. This preserves the intended one-registration/many-tcon behavior: a registration id represents a net/share pair, and notify handling acts on a live representative selected at use time. It also preserves CLIENT_MOVE ordering for the representative tcon because the old-IP unregister is sent before cifs_swn_register() sends the new-IP register.

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 fed979a7e082bd9f25f9002c3c4f8740dacd0bc8 <aa3c0cab4b28c5007ec570c63e1d6ad6943ed0fd; patch: 6.6.145; fed979a7e082bd9f25f9002c3c4f8740dacd0bc8 <51d18db392e5386a7bb9e816d611f14e600cca3c; fed979a7e082bd9f25f9002c3c4f8740dacd0bc8 <0700f946659d0ab2352ec8a9b1c6fc74b13a27d7; patch: 6.18.39; patch: 0; patch: 7.2-rc1; patch: 6.1.178; fed979a7e082bd9f25f9002c3c4f8740dacd0bc8 <ec457f9afe5ae9538bdcd58fd4cb442b9787e183; patch: 6.12.97; 5.11; fed979a7e082bd9f25f9002c3c4f8740dacd0bc8 <91b8a58c6ac15c7db6518f696389933282f88da7; fed979a7e082bd9f25f9002c3c4f8740dacd0bc8 <945b4a4a54497db1dcb2f20ef801a84e884dac21; patch: 7.1.4

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.