CVE-2026-68186

CVE CVE-2026-68186EUVD EUVD-2026-55287Veröffentlicht 2026-08-10T11:59:58.000Z

Was das Advisory beschreibt

In the Linux kernel, the following vulnerability has been resolved: binfmt_misc: set have_execfd only once the interpreter is opened load_misc_binary() raises bprm->have_execfd as soon as it sees the 'O' (or 'C') flag. This happens well before it opens the interpreter. If that open fails the flag stays set on the bprm. binfmt_misc is at the head of the format list so an interpreter open failure that returns -ENOEXEC lets the search fall through to a later format. This means it runs the matched binary directly having never staged an interpreter. So bprm->executable is NULL while have_execfd falsely claims a descriptor is present. Consequently, begin_new_exec() dereferences the missing executable: would_dump(bprm, bprm->executable); and NULL derefs. Had it not, the hand-off later in the same function would have failed anyway. FD_ADD(0, bprm->executable) rejects a NULL file with -ENOMEM. Both sites are past the point of no return so the exec cannot be unwound either way. This can be reached by unprivileged users as binfmt_misc can be mounted in user namespaces. So a user can register an 'O' entry whose interpreter lives on a FUSE mount, have the FUSE server fail the open with -ENOEXEC and execute a native ELF file that matches the entry. have_execfd only means anything alongside the executable it describes which is not set until the interpreter has been opened and staged. So lets raise it there, next to execfd_creds, which is already set at that point. An open failure now leaves it clear, so the fallback format derives credentials from the binary and emits no AT_EXECFD, as it would for any native exec. The argv rewrite load_misc_binary() performs before the open is still not undone. This means the binary sees the interpreter path in argv[0] and its own path in argv[1] but that predates this change and only became observable once the exec stopped faulting.

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 patch: 6.12.101; patch: 7.1.6; bc2bf338d54b7aadaed49bb45b9e10d4592b2a46 <bbf5f639918dc011aaf60aab8480218758ee68c5; patch: 7.2-rc5; patch: 6.18.42; bc2bf338d54b7aadaed49bb45b9e10d4592b2a46 <5ccc99d58f94fad258c9c375715b3974e48620e8; bc2bf338d54b7aadaed49bb45b9e10d4592b2a46 <0f19d54e2524f0bf183b82f365ae4e49b4a2f788; 5.8; patch: 6.6.148; bc2bf338d54b7aadaed49bb45b9e10d4592b2a46 <1cd4e9b7967dab48c9f79a00b06ffff7208c0993; patch: 0; bc2bf338d54b7aadaed49bb45b9e10d4592b2a46 <2dd0298905e97795a9c5ec30cf5b41975f821632

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.