{"id":"CVE-2026-74376","state":"PUBLISHED","title":"md/raid10: reset read_slot when reusing r10bio for discard","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmd/raid10: reset read_slot when reusing r10bio for discard\n\nput_all_bios() always drops devs[i].bio, but it only drops\ndevs[i].repl_bio when r10_bio->read_slot < 0. If discard reuses an\nr10bio that was previously used for a read, read_slot can still be\nnon-negative, and discard cleanup can skip bio_put() on repl_bio.\n\nReset read_slot to -1 when preparing an r10bio for discard so the\nreplacement bio is always released correctly.","publishedAt":"2026-08-15T05:58:55.023Z","updatedAt":"2026-10-16T18:55:36.173Z","severity":{"score":9.8,"label":"Critical","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d30588b2731fb01e1616cf16c3fe79a1443e29aa","status":"affected","lessThan":"3cb2a606ce4902eceabe68338df0653312f861f8","versionType":"git"},{"version":"d30588b2731fb01e1616cf16c3fe79a1443e29aa","status":"affected","lessThan":"561c9711e4f545d6464a023168bdee03b00fa945","versionType":"git"},{"version":"d30588b2731fb01e1616cf16c3fe79a1443e29aa","status":"affected","lessThan":"ce3030e92f14362880055de5fe3c258971118853","versionType":"git"},{"version":"d30588b2731fb01e1616cf16c3fe79a1443e29aa","status":"affected","lessThan":"742e4afd247d9c972695227716b03d432a7e1d26","versionType":"git"},{"version":"d30588b2731fb01e1616cf16c3fe79a1443e29aa","status":"affected","lessThan":"b7313f23ea5a79b199a007bfad64a866cc2c22e7","versionType":"git"},{"version":"d30588b2731fb01e1616cf16c3fe79a1443e29aa","status":"affected","lessThan":"eb04e3e9c14ed15914f5fd2eae8b6435f54f095f","versionType":"git"},{"version":"d30588b2731fb01e1616cf16c3fe79a1443e29aa","status":"affected","lessThan":"6b8a26af065ddc93de2aa5c9f0df98dce9723442","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/md/raid10.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.13","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.13","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":["drivers/md/raid10.c"]}],"references":["https://git.kernel.org/stable/c/3cb2a606ce4902eceabe68338df0653312f861f8","https://git.kernel.org/stable/c/561c9711e4f545d6464a023168bdee03b00fa945","https://git.kernel.org/stable/c/ce3030e92f14362880055de5fe3c258971118853","https://git.kernel.org/stable/c/742e4afd247d9c972695227716b03d432a7e1d26","https://git.kernel.org/stable/c/b7313f23ea5a79b199a007bfad64a866cc2c22e7","https://git.kernel.org/stable/c/eb04e3e9c14ed15914f5fd2eae8b6435f54f095f","https://git.kernel.org/stable/c/6b8a26af065ddc93de2aa5c9f0df98dce9723442"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/74xxx/CVE-2026-74376.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-74376","state":"PUBLISHED","datePublished":"2026-08-15T05:58:55.023Z","dateUpdated":"2026-10-16T18:55:36.173Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-15T05:44:03.889Z"},"containers":{"cna":{"title":"md/raid10: reset read_slot when reusing r10bio for discard","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmd/raid10: reset read_slot when reusing r10bio for discard\n\nput_all_bios() always drops devs[i].bio, but it only drops\ndevs[i].repl_bio when r10_bio->read_slot < 0. If discard reuses an\nr10bio that was previously used for a read, read_slot can still be\nnon-negative, and discard cleanup can skip bio_put() on repl_bio.\n\nReset read_slot to -1 when preparing an r10bio for discard so the\nreplacement bio is always released correctly."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d30588b2731fb01e1616cf16c3fe79a1443e29aa","status":"affected","lessThan":"3cb2a606ce4902eceabe68338df0653312f861f8","versionType":"git"},{"version":"d30588b2731fb01e1616cf16c3fe79a1443e29aa","status":"affected","lessThan":"561c9711e4f545d6464a023168bdee03b00fa945","versionType":"git"},{"version":"d30588b2731fb01e1616cf16c3fe79a1443e29aa","status":"affected","lessThan":"ce3030e92f14362880055de5fe3c258971118853","versionType":"git"},{"version":"d30588b2731fb01e1616cf16c3fe79a1443e29aa","status":"affected","lessThan":"742e4afd247d9c972695227716b03d432a7e1d26","versionType":"git"},{"version":"d30588b2731fb01e1616cf16c3fe79a1443e29aa","status":"affected","lessThan":"b7313f23ea5a79b199a007bfad64a866cc2c22e7","versionType":"git"},{"version":"d30588b2731fb01e1616cf16c3fe79a1443e29aa","status":"affected","lessThan":"eb04e3e9c14ed15914f5fd2eae8b6435f54f095f","versionType":"git"},{"version":"d30588b2731fb01e1616cf16c3fe79a1443e29aa","status":"affected","lessThan":"6b8a26af065ddc93de2aa5c9f0df98dce9723442","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/md/raid10.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.13","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.13","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":["drivers/md/raid10.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/3cb2a606ce4902eceabe68338df0653312f861f8"},{"url":"https://git.kernel.org/stable/c/561c9711e4f545d6464a023168bdee03b00fa945"},{"url":"https://git.kernel.org/stable/c/ce3030e92f14362880055de5fe3c258971118853"},{"url":"https://git.kernel.org/stable/c/742e4afd247d9c972695227716b03d432a7e1d26"},{"url":"https://git.kernel.org/stable/c/b7313f23ea5a79b199a007bfad64a866cc2c22e7"},{"url":"https://git.kernel.org/stable/c/eb04e3e9c14ed15914f5fd2eae8b6435f54f095f"},{"url":"https://git.kernel.org/stable/c/6b8a26af065ddc93de2aa5c9f0df98dce9723442"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - iSCSI/NVMe-oF targets and appliances commonly expose RAID10-backed LUNs; remote SCSI UNMAP maps through target_core iblock_execute_unmap()/blkdev_issue_discard() to md_handle_request() and raid10_handle_discard without local access.\nAC:L - The attacker controls both pool poisoning reads and triggering discards; mempool-reused r10bios retain a non-negative read_slot from prior reads, so each qualifying discard reliably skips repl_bio bio_put() when replacement mirrors exist.\nPR:N - Network UNMAP from an iSCSI/NVMe-oF client needs no Linux UID or capabilities on the target; local exploitation only needs O_RDWR on the md device or FITRIM (CAP_SYS_ADMIN, obtainable in user namespaces), both below High.\nUI:N - No interactive victim action—exploitation uses normal block-layer discard requests (fstrim cron, UNMAP, BLKDISCARD) issued or scripted by the attacker without cooperation.\nS:U - The bug corrupts/leaks kernel bio objects within the same host kernel security domain; it does not cross VM, container, or IOMMU boundaries.\nC:H - Stale read_slot misclassifies repl_bio as rdev in the r10dev union during put_all_bios(), leaking live bios holding kernel pointers and enabling heap-grooming read primitives; scored High when uncertain per memory-corruption guidance.\nI:H - The read_slot/repl_bio union type confusion skips bio_put() on attacker-submitted replacement discard clones, enabling slab manipulation for arbitrary kernel writes; type confusion maps to High integrity impact per kernel CVSS guidance.\nA:H - Repeated read-then-discard cycles leak bios on every hit; on busy RAID10 storage servers this exhausts kmem and can trigger OOM killer or panic, so Availability is High rather than Low per the conservative rule."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T05:46:28.657Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"5.15.212"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.1.178"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.6.145"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.12.97"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.18.40"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"7.1.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-74376","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T18:54:45.646885Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-16T18:55:36.173Z"}}]}}}