{"id":"CVE-2026-90220","published":"2026-09-17T17:17:17.440","lastModified":"2026-09-17T17:17:17.440","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: seq: Don't leak the extension cell pointer in the bounce payload\n\nThe bounce_error_event() embeds the failed event in the bounce payload\nby pointing data.ext.ptr at it.  When that event is a queued\nvariable-length event, its own data.ext.ptr holds the address of its\nfirst extension cell, put there by snd_seq_event_dup().  The payload\ngoes out verbatim through snd_seq_expand_var_event(), so the address\nreaches userspace.\n\nThat is the same address commit 705dd6dcbc0e (\"ALSA: seq: Clear\nvariable event pointer on read\") removed from the event header.  The\nread path still clears it there, just above the call that expands the\npayload.\n\nEmbed a sanitised copy instead, treated exactly as snd_seq_read()\ntreats the header.  A stack copy is enough because delivery is\nsynchronous and snd_seq_event_dup() copies before returning.\n\nAn unprivileged client reaches this by setting SNDRV_SEQ_FILTER_BOUNCE,\nqueueing a variable-length event to a port that does not exist and\nreading the bounce back.  Eight bytes on 64-bit, from its own pool.","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/42c3f856d13a91a0d4c302a0c6854813621136db","tags":[]},{"url":"https://git.kernel.org/stable/c/59e1592d3c270ff4642d5d6dc55c545306eb0693","tags":[]},{"url":"https://git.kernel.org/stable/c/6e6e471eef1d5d8cb056c7d364023fe048249204","tags":[]},{"url":"https://git.kernel.org/stable/c/b1e8d40663997aacaa198f37ce6893e07aaba77a","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}