{"id":"CVE-2026-90220","state":"PUBLISHED","title":"ALSA: seq: Don't leak the extension cell pointer in the bounce payload","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.","publishedAt":"2026-09-17T16:07:31.423Z","updatedAt":"2026-10-30T12:34:49.721Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"05e2358fec8812c37516ccea63bc4b9956d864ba","status":"affected","lessThan":"c92b2e6e418a3885758438dddcead6e954a9e095","versionType":"git"},{"version":"93d260ce43a81df579c98bee92b91316df9c1c57","status":"affected","lessThan":"42c3f856d13a91a0d4c302a0c6854813621136db","versionType":"git"},{"version":"dae23c545eb5a2be3b27a82fd0f611894fb8ab69","status":"affected","lessThan":"b1e8d40663997aacaa198f37ce6893e07aaba77a","versionType":"git"},{"version":"efc86691e4d8083d9e380ea95042c2cf679f65fd","status":"affected","lessThan":"6e6e471eef1d5d8cb056c7d364023fe048249204","versionType":"git"},{"version":"efc86691e4d8083d9e380ea95042c2cf679f65fd","status":"affected","lessThan":"59e1592d3c270ff4642d5d6dc55c545306eb0693","versionType":"git"},{"version":"eae296065ede41a24040e6a7c909ec970f78b4eb","status":"affected","versionType":"git"},{"version":"0527a56cb327021cb73167cfddf0e49efa043500","status":"affected","versionType":"git"},{"version":"6.12.97","status":"affected","lessThan":"6.12.110","versionType":"semver"},{"version":"6.18.40","status":"affected","lessThan":"6.18.52","versionType":"semver"},{"version":"6.6.160","status":"affected","lessThan":"6.7","versionType":"semver"},{"version":"7.1.5","status":"affected","lessThan":"7.2","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["sound/core/seq/seq_clientmgr.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.2","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.2","versionType":"semver"},{"version":"6.12.110","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.52","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.6","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["sound/core/seq/seq_clientmgr.c"]}],"references":["https://git.kernel.org/stable/c/c92b2e6e418a3885758438dddcead6e954a9e095","https://git.kernel.org/stable/c/42c3f856d13a91a0d4c302a0c6854813621136db","https://git.kernel.org/stable/c/b1e8d40663997aacaa198f37ce6893e07aaba77a","https://git.kernel.org/stable/c/6e6e471eef1d5d8cb056c7d364023fe048249204","https://git.kernel.org/stable/c/59e1592d3c270ff4642d5d6dc55c545306eb0693"],"weaknesses":[],"ingestedAt":"2026-10-30T12:54:04.478Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/90xxx/CVE-2026-90220.json","commit":"1f312381e38164a43607eebab851b151dd16861e","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-90220","state":"PUBLISHED","datePublished":"2026-09-17T16:07:31.423Z","dateUpdated":"2026-10-30T12:34:49.721Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-11T19:38:34.793Z"},"containers":{"cna":{"title":"ALSA: seq: Don't leak the extension cell pointer in the bounce payload","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"05e2358fec8812c37516ccea63bc4b9956d864ba","status":"affected","lessThan":"c92b2e6e418a3885758438dddcead6e954a9e095","versionType":"git"},{"version":"93d260ce43a81df579c98bee92b91316df9c1c57","status":"affected","lessThan":"42c3f856d13a91a0d4c302a0c6854813621136db","versionType":"git"},{"version":"dae23c545eb5a2be3b27a82fd0f611894fb8ab69","status":"affected","lessThan":"b1e8d40663997aacaa198f37ce6893e07aaba77a","versionType":"git"},{"version":"efc86691e4d8083d9e380ea95042c2cf679f65fd","status":"affected","lessThan":"6e6e471eef1d5d8cb056c7d364023fe048249204","versionType":"git"},{"version":"efc86691e4d8083d9e380ea95042c2cf679f65fd","status":"affected","lessThan":"59e1592d3c270ff4642d5d6dc55c545306eb0693","versionType":"git"},{"version":"eae296065ede41a24040e6a7c909ec970f78b4eb","status":"affected","versionType":"git"},{"version":"0527a56cb327021cb73167cfddf0e49efa043500","status":"affected","versionType":"git"},{"version":"6.12.97","status":"affected","lessThan":"6.12.110","versionType":"semver"},{"version":"6.18.40","status":"affected","lessThan":"6.18.52","versionType":"semver"},{"version":"6.6.160","status":"affected","lessThan":"6.7","versionType":"semver"},{"version":"7.1.5","status":"affected","lessThan":"7.2","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["sound/core/seq/seq_clientmgr.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"7.2","status":"affected"},{"version":"0","status":"unaffected","lessThan":"7.2","versionType":"semver"},{"version":"6.12.110","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.52","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.6","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["sound/core/seq/seq_clientmgr.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/c92b2e6e418a3885758438dddcead6e954a9e095"},{"url":"https://git.kernel.org/stable/c/42c3f856d13a91a0d4c302a0c6854813621136db"},{"url":"https://git.kernel.org/stable/c/b1e8d40663997aacaa198f37ce6893e07aaba77a"},{"url":"https://git.kernel.org/stable/c/6e6e471eef1d5d8cb056c7d364023fe048249204"},{"url":"https://git.kernel.org/stable/c/59e1592d3c270ff4642d5d6dc55c545306eb0693"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:34:49.721Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12.97","versionEndExcluding":"6.12.110"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.18.40","versionEndExcluding":"6.18.52"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.2","versionEndExcluding":"7.2.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.2","versionEndExcluding":"7.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.1.5"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}