CVE-2026-99234 Fuga de recursos en histogramas de field variables de tracing al fallar un comando

Afectados

• Linux

  desde 02205a6752f223779a1b0e9e8ffacbea6e717851 hasta antes de f21351d1c4cdcc6a68f03636a407c2af1a5e1e10desde 02205a6752f223779a1b0e9e8ffacbea6e717851 hasta antes de dba0f492703956801149cc70b39d2650a37995c3desde 02205a6752f223779a1b0e9e8ffacbea6e717851 hasta antes de a3d7ffd2409700748a495b645948fef48199206edesde 02205a6752f223779a1b0e9e8ffacbea6e717851 hasta antes de aae0ccd7326eef78dcdefffef3d1253e6f0615cadesde 02205a6752f223779a1b0e9e8ffacbea6e717851 hasta antes de 8482ec5b65f606d5bbcec518e0afc69ad65ca414desde 02205a6752f223779a1b0e9e8ffacbea6e717851 hasta antes de 431959fc76456cbba539279fe8967aa9391e6f23desde 02205a6752f223779a1b0e9e8ffacbea6e717851 hasta antes de 5afb9317e2eeb1c7021a82995ce244fda5a4bd4fdesde 02205a6752f223779a1b0e9e8ffacbea6e717851 hasta antes de d0090baf02dd08f6e909f36f0ad54a4e80f5e79bdesde 02205a6752f223779a1b0e9e8ffacbea6e717851 hasta antes de 91c14d6c13096091c56304120aaa26e479130b8b

• Linux

  4.17

Qué hacer

1. Verificá si usás Linux y en qué versión.
2. Actualizá a la versión corregida que indique el fabricante en su aviso o aplicá su mitigación.
3. Revisá registros y accesos de los sistemas expuestos para descartar un uso previo.

Calculadora CVSS

Esta vulnerabilidad todavía no tiene vector CVSS publicado.

Descripción original

In the Linux kernel, the following vulnerability has been resolved: tracing: Unregister field variable histograms when the command fails An action that names a field on another event needs that field as a variable, so create_field_var_hist() registers a second hist trigger on that event to provide it, and records it in target_hist_data->field_var_hists[]. If a later part of the same command fails, create_actions() returns an error and event_hist_trigger_parse() jumps to out_free. The write fails with -EINVAL and sched_switch gets no trigger, but: # echo 'hist:keys=pid:ts0=common_timestamp.usecs' >> \ events/sched/sched_waking/trigger # echo 'my_synth u64 lat; int a; int b' >> synthetic_events # echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0:\ onmatch(sched.sched_waking).my_synth($wakeup_lat,prio,nosuchfld)'\ >> events/sched/sched_switch/trigger # cat events/sched/sched_waking/trigger hist:keys=pid:vals=hitcount:ts0=common_timestamp.usecs:sort=hitcount:size=2048:clock=global [active] hist:keys=pid:vals=hitcount:synthetic_prio=prio:sort=hitcount:size=2048 [active] The second histogram is the one created for 'prio'. It is still active and still counting. out_free reaches destroy_field_var_hists(), which frees the field_var_hists[] entries, but never unregister_field_var_hists(), which is what removes the triggers and runs only from event_hist_trigger_free(). The entry is freed and the trigger is left with nothing tracking it. Unregister the field variable histograms in out_free as well, and record each one as soon as its trigger is registered rather than after the lookup that follows it, so no exit can leave a registered trigger untracked. The entry then belongs to field_var_hists[] and is released by destroy_field_var_hists(), so freeing it on that exit would be a double free.

Referencias (9)

• git.kernel.org/stable/c/f21351d1c4cdcc6a68f03636a407c2af1a5e1e10
• git.kernel.org/stable/c/dba0f492703956801149cc70b39d2650a37995c3
• git.kernel.org/stable/c/a3d7ffd2409700748a495b645948fef48199206e
• git.kernel.org/stable/c/aae0ccd7326eef78dcdefffef3d1253e6f0615ca
• git.kernel.org/stable/c/8482ec5b65f606d5bbcec518e0afc69ad65ca414
• git.kernel.org/stable/c/431959fc76456cbba539279fe8967aa9391e6f23
• git.kernel.org/stable/c/5afb9317e2eeb1c7021a82995ce244fda5a4bd4f
• git.kernel.org/stable/c/d0090baf02dd08f6e909f36f0ad54a4e80f5e79b
• git.kernel.org/stable/c/91c14d6c13096091c56304120aaa26e479130b8b

Resumen traducido automáticamente de la descripción original. Fuente: Nureq Monitor. Cómo funciona.