CVE-2026-97921

CVE CVE-2026-97921EUVD EUVD-2026-86775Veröffentlicht 2026-09-25T10:22:41.000Z

Was das Advisory beschreibt

In the Linux kernel, the following vulnerability has been resolved: tracing: Free histogram the field rejected for a bad modifier Writing a hist trigger whose value or variable carries a modifier that is not allowed there leaks the fields that were built for it. __create_val_field() takes the field from parse_expr() and stores it in hist_data->fields[] only after the modifier checks have run: hist_field = parse_expr(hist_data, file, field_str, flags, var_name, &n_subexprs); ... if (hist_field->flags & HIST_FIELD_FL_VAR) { if (hist_field->flags & (...)) goto err; } else { if (hist_field->flags & (...)) goto err; } hist_data->fields[val_idx] = hist_field; Both checks jump past that store, and the err label returns without freeing anything. The error unwinds to create_hist_data(), which calls destroy_hist_data() -> destroy_hist_fields(), and that reaches a field only by walking fields[]. A field that never got there is unreachable. commit e0213434fe3e ("tracing: Do not let histogram values have some modifiers") set ret to -EINVAL and fell through to the store, which left the field owned by fields[] and freed along with the rest of hist_data. Splitting the check into a value case and a variable case replaced that fall-through with a goto that skips it. With CONFIG_DEBUG_KMEMLEAK, 200 writes of # echo 'hist:keys=prev_pid:vals=next_pid.log2' > \ events/sched/sched_switch/trigger each correctly rejected with -EINVAL, leave 332 unreferenced objects (63744 bytes) reported at create_hist_field(); 200 install and remove cycles of a valid trigger leave none. A '.log2' field is two allocations, since create_hist_field() puts the plain field in operands[0] of the log2 field, and both are reported. Use destroy_hist_field() rather than __destroy_hist_field() so that operands[0] is freed as well. It returns early for HIST_FIELD_FL_VAR_REF, which is what an operand owned by hist_data->var_refs[] needs; the rejected field itself is never a var ref, because a var ref never carries a modifier flag.

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: 6.12.111; 8d505d06d7330f5d67d3e5e9e1c647fb0b10ddad; patch: 6.18.53; e30fbc618e97b38dbb49f1d44dcd0778d3f23b8c <230234d12ce42ab04132a32c3a848f07a5d27a71; 6.1.33 <6.2; 6.3.7 <6.4; patch: 7.2.7; e30fbc618e97b38dbb49f1d44dcd0778d3f23b8c <891c21f6d5673b2a519b536243bfc6dd2d35beb6; 7403630eb94c1d664fb873f967427ef2f6ee3699; 6.4; patch: 0; patch: 7.3-rc3; e30fbc618e97b38dbb49f1d44dcd0778d3f23b8c <e787361bb6b0026ea3eb4d3fa7a304c7fcb99555; e30fbc618e97b38dbb49f1d44dcd0778d3f23b8c <b22dc0add7d72b8bd9cae3188db0dd65da1c8652

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.