{"id":"CVE-2026-74339","state":"PUBLISHED","title":"ALSA: seq: Clear variable event pointer on read","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: seq: Clear variable event pointer on read\n\nsnd_seq_read() copies a queued variable-length event header to userspace\nbefore expanding the payload. Queued variable-length events use\nSNDRV_SEQ_EXT_CHAINED internally, and data.ext.ptr points at the first\nextension cell.\n\nThe read side strips SNDRV_SEQ_EXT_* bits from data.ext.len before the\ncopy, but it leaves data.ext.ptr untouched. A userspace sequencer client\ncan therefore write a direct variable event to itself and read back the\nextension-cell kernel address from the returned header.\n\nClear the temporary header pointer before copy_to_user(). The original\nqueued event remains unchanged and is still passed to\nsnd_seq_expand_var_event(), so payload expansion keeps using the\ninternal chain.","publishedAt":"2026-08-15T05:58:29.888Z","updatedAt":"2026-10-30T12:29:45.739Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"8a631e1aaa1ebbc9de916927fa01707244e18291","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"14fe4f75fd5309d6b75f8e840ada88912b374207","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"f29243c211928114f8b906e0a3fee77c236f14c8","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"e0c3edd86414534cfd179fefe45b38c29c01ae7a","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"6b52211eba213c461f68922708a99d8190c1fcd5","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"74ac1ce1f4afdb3b80b6742fa28fb86c8c51d31b","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"c2ac9287e89916da684c2a548798351e63eb59ee","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"705dd6dcbc0ea87351c660c1a6443f85f1001c76","versionType":"git"}],"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":"2.6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.12","versionType":"semver"},{"version":"5.10.273","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.212","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.178","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","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/8a631e1aaa1ebbc9de916927fa01707244e18291","https://git.kernel.org/stable/c/14fe4f75fd5309d6b75f8e840ada88912b374207","https://git.kernel.org/stable/c/f29243c211928114f8b906e0a3fee77c236f14c8","https://git.kernel.org/stable/c/e0c3edd86414534cfd179fefe45b38c29c01ae7a","https://git.kernel.org/stable/c/6b52211eba213c461f68922708a99d8190c1fcd5","https://git.kernel.org/stable/c/74ac1ce1f4afdb3b80b6742fa28fb86c8c51d31b","https://git.kernel.org/stable/c/c2ac9287e89916da684c2a548798351e63eb59ee","https://git.kernel.org/stable/c/705dd6dcbc0ea87351c660c1a6443f85f1001c76"],"weaknesses":[],"ingestedAt":"2026-10-30T12:48:04.825Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/74xxx/CVE-2026-74339.json","commit":"1f312381e38164a43607eebab851b151dd16861e","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-74339","state":"PUBLISHED","datePublished":"2026-08-15T05:58:29.888Z","dateUpdated":"2026-10-30T12:29:45.739Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-15T05:44:03.885Z"},"containers":{"cna":{"title":"ALSA: seq: Clear variable event pointer on read","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: seq: Clear variable event pointer on read\n\nsnd_seq_read() copies a queued variable-length event header to userspace\nbefore expanding the payload. Queued variable-length events use\nSNDRV_SEQ_EXT_CHAINED internally, and data.ext.ptr points at the first\nextension cell.\n\nThe read side strips SNDRV_SEQ_EXT_* bits from data.ext.len before the\ncopy, but it leaves data.ext.ptr untouched. A userspace sequencer client\ncan therefore write a direct variable event to itself and read back the\nextension-cell kernel address from the returned header.\n\nClear the temporary header pointer before copy_to_user(). The original\nqueued event remains unchanged and is still passed to\nsnd_seq_expand_var_event(), so payload expansion keeps using the\ninternal chain."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"8a631e1aaa1ebbc9de916927fa01707244e18291","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"14fe4f75fd5309d6b75f8e840ada88912b374207","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"f29243c211928114f8b906e0a3fee77c236f14c8","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"e0c3edd86414534cfd179fefe45b38c29c01ae7a","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"6b52211eba213c461f68922708a99d8190c1fcd5","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"74ac1ce1f4afdb3b80b6742fa28fb86c8c51d31b","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"c2ac9287e89916da684c2a548798351e63eb59ee","versionType":"git"},{"version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","status":"affected","lessThan":"705dd6dcbc0ea87351c660c1a6443f85f1001c76","versionType":"git"}],"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":"2.6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.12","versionType":"semver"},{"version":"5.10.273","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.212","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.178","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","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/8a631e1aaa1ebbc9de916927fa01707244e18291"},{"url":"https://git.kernel.org/stable/c/14fe4f75fd5309d6b75f8e840ada88912b374207"},{"url":"https://git.kernel.org/stable/c/f29243c211928114f8b906e0a3fee77c236f14c8"},{"url":"https://git.kernel.org/stable/c/e0c3edd86414534cfd179fefe45b38c29c01ae7a"},{"url":"https://git.kernel.org/stable/c/6b52211eba213c461f68922708a99d8190c1fcd5"},{"url":"https://git.kernel.org/stable/c/74ac1ce1f4afdb3b80b6742fa28fb86c8c51d31b"},{"url":"https://git.kernel.org/stable/c/c2ac9287e89916da684c2a548798351e63eb59ee"},{"url":"https://git.kernel.org/stable/c/705dd6dcbc0ea87351c660c1a6443f85f1001c76"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:29:45.739Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"5.10.273"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"5.15.212"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.1.178"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.6.145"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.12.97"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"6.18.40"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"7.1.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.12","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}