{"id":"CVE-2024-27435","state":"PUBLISHED","title":"nvme: fix reconnection fail due to reserved tag allocation","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnvme: fix reconnection fail due to reserved tag allocation\n\nWe found a issue on production environment while using NVMe over RDMA,\nadmin_q reconnect failed forever while remote target and network is ok.\nAfter dig into it, we found it may caused by a ABBA deadlock due to tag\nallocation. In my case, the tag was hold by a keep alive request\nwaiting inside admin_q, as we quiesced admin_q while reset ctrl, so the\nrequest maked as idle and will not process before reset success. As\nfabric_q shares tagset with admin_q, while reconnect remote target, we\nneed a tag for connect command, but the only one reserved tag was held\nby keep alive command which waiting inside admin_q. As a result, we\nfailed to reconnect admin_q forever. In order to fix this issue, I\nthink we should keep two reserved tags for admin queue.","publishedAt":"2024-05-17T12:12:36.439Z","updatedAt":"2026-08-05T11:29:48.601Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"ed01fee283a067c72b2d6500046080dbc1bb9dae","status":"affected","lessThan":"149afee5c7418ec5db9d7387b9c9a5c1eb7ea2a8","versionType":"git"},{"version":"ed01fee283a067c72b2d6500046080dbc1bb9dae","status":"affected","lessThan":"ff2f90f88d78559802466ad1c84ac5bda4416b3a","versionType":"git"},{"version":"ed01fee283a067c72b2d6500046080dbc1bb9dae","status":"affected","lessThan":"6851778504cdb49431809b4ba061903d5f592c96","versionType":"git"},{"version":"ed01fee283a067c72b2d6500046080dbc1bb9dae","status":"affected","lessThan":"262da920896e2f2ab0e3947d9dbee0aa09045818","versionType":"git"},{"version":"ed01fee283a067c72b2d6500046080dbc1bb9dae","status":"affected","lessThan":"de105068fead55ed5c07ade75e9c8e7f86a00d1d","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/nvme/host/core.c","drivers/nvme/host/fabrics.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.12","versionType":"semver"},{"version":"6.1.83","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.23","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.7.11","status":"unaffected","lessThanOrEqual":"6.7.*","versionType":"semver"},{"version":"6.8.2","status":"unaffected","lessThanOrEqual":"6.8.*","versionType":"semver"},{"version":"6.9","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/nvme/host/core.c","drivers/nvme/host/fabrics.h"]}],"references":["https://git.kernel.org/stable/c/149afee5c7418ec5db9d7387b9c9a5c1eb7ea2a8","https://git.kernel.org/stable/c/ff2f90f88d78559802466ad1c84ac5bda4416b3a","https://git.kernel.org/stable/c/6851778504cdb49431809b4ba061903d5f592c96","https://git.kernel.org/stable/c/262da920896e2f2ab0e3947d9dbee0aa09045818","https://git.kernel.org/stable/c/de105068fead55ed5c07ade75e9c8e7f86a00d1d"],"weaknesses":[],"ingestedAt":"2026-10-29T20:07:10.607Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2024/27xxx/CVE-2024-27435.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2024-27435","state":"PUBLISHED","datePublished":"2024-05-17T12:12:36.439Z","dateUpdated":"2026-08-05T11:29:48.601Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2024-02-25T13:47:42.687Z"},"containers":{"cna":{"title":"nvme: fix reconnection fail due to reserved tag allocation","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnvme: fix reconnection fail due to reserved tag allocation\n\nWe found a issue on production environment while using NVMe over RDMA,\nadmin_q reconnect failed forever while remote target and network is ok.\nAfter dig into it, we found it may caused by a ABBA deadlock due to tag\nallocation. In my case, the tag was hold by a keep alive request\nwaiting inside admin_q, as we quiesced admin_q while reset ctrl, so the\nrequest maked as idle and will not process before reset success. As\nfabric_q shares tagset with admin_q, while reconnect remote target, we\nneed a tag for connect command, but the only one reserved tag was held\nby keep alive command which waiting inside admin_q. As a result, we\nfailed to reconnect admin_q forever. In order to fix this issue, I\nthink we should keep two reserved tags for admin queue."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"ed01fee283a067c72b2d6500046080dbc1bb9dae","status":"affected","lessThan":"149afee5c7418ec5db9d7387b9c9a5c1eb7ea2a8","versionType":"git"},{"version":"ed01fee283a067c72b2d6500046080dbc1bb9dae","status":"affected","lessThan":"ff2f90f88d78559802466ad1c84ac5bda4416b3a","versionType":"git"},{"version":"ed01fee283a067c72b2d6500046080dbc1bb9dae","status":"affected","lessThan":"6851778504cdb49431809b4ba061903d5f592c96","versionType":"git"},{"version":"ed01fee283a067c72b2d6500046080dbc1bb9dae","status":"affected","lessThan":"262da920896e2f2ab0e3947d9dbee0aa09045818","versionType":"git"},{"version":"ed01fee283a067c72b2d6500046080dbc1bb9dae","status":"affected","lessThan":"de105068fead55ed5c07ade75e9c8e7f86a00d1d","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/nvme/host/core.c","drivers/nvme/host/fabrics.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.12","versionType":"semver"},{"version":"6.1.83","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.23","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.7.11","status":"unaffected","lessThanOrEqual":"6.7.*","versionType":"semver"},{"version":"6.8.2","status":"unaffected","lessThanOrEqual":"6.8.*","versionType":"semver"},{"version":"6.9","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/nvme/host/core.c","drivers/nvme/host/fabrics.h"]}],"references":[{"url":"https://git.kernel.org/stable/c/149afee5c7418ec5db9d7387b9c9a5c1eb7ea2a8"},{"url":"https://git.kernel.org/stable/c/ff2f90f88d78559802466ad1c84ac5bda4416b3a"},{"url":"https://git.kernel.org/stable/c/6851778504cdb49431809b4ba061903d5f592c96"},{"url":"https://git.kernel.org/stable/c/262da920896e2f2ab0e3947d9dbee0aa09045818"},{"url":"https://git.kernel.org/stable/c/de105068fead55ed5c07ade75e9c8e7f86a00d1d"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - The affected code is the NVMe-over-Fabrics host driver (nvme-tcp/nvme-rdma/nvme-fc), and the controller reset that opens the race window is triggered directly from remote peer input — `nvme_tcp_state_change()` fires error recovery on a peer FIN/RST, and the receive path calls `nvme_tcp_error_recovery()` on any malformed PDU. A remote or on-path attacker against the NVMe/TCP connection (port 4420) can drive the vulnerable path without local access.\nAC:L - The attacker controls the reset side of the race and can force error recovery/reconnect cycles arbitrarily many times (reconnect re-arms the keep-alive timer each round), while the keep-alive period is deterministic at kato/2, so the window can be hit by retry and by timing; the bug was also observed occurring spontaneously in production. Once won, the leaked reserved tag is permanent — no further conditions are needed.\nPR:N - No credentials on the victim host are required — the triggering events (TCP FIN/RST, malformed NVMe/TCP PDU, unresponsive target) are handled by `nvme_tcp_state_change()` and the recv path before or independent of any NVMe-level authentication, and NVMe/TCP deployments commonly run with no DH-HMAC-CHAP or TLS at all.\nUI:N - Exploitation requires no action from any user or administrator; an already-established NVMe-oF connection is a system configuration precondition, not victim interaction, and the keep-alive/reset machinery runs autonomously in kernel workqueues.\nS:U - The impact is confined to the kernel and the host's own storage stack — no security authority boundary such as a VM, IOMMU, or sandbox is crossed.\nC:N - The defect is a reserved-tag leak causing an ABBA allocation deadlock; no memory is read out of bounds, no freed object is accessed, and no kernel data is disclosed to the attacker.\nI:N - There is no memory corruption, out-of-bounds write, or control-flow primitive — the only consequence is that a blk-mq tag is never returned, so no attacker-influenced data modification is possible.\nA:H - The admin queue can never reconnect (\"failed to reconnect admin_q forever\"), because the admin tagset is not reallocated on reconnect and the connect command's reserved tag allocation fails with -EAGAIN indefinitely, producing a permanent loss of the NVMe-oF storage path plus eventual controller deletion (and a hung, unkillable teardown worker blocked on queue freeze) — total availability loss for storage that is frequently the system's root or primary data volume."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T11:29:48.601Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.12","versionEndExcluding":"6.1.83"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.12","versionEndExcluding":"6.6.23"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.12","versionEndExcluding":"6.7.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.12","versionEndExcluding":"6.8.2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.12","versionEndExcluding":"6.9"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":5.5,"attackVector":"LOCAL","baseSeverity":"MEDIUM","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","integrityImpact":"NONE","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"HIGH","privilegesRequired":"LOW","confidentialityImpact":"NONE"}},{"other":{"type":"ssvc","content":{"timestamp":"2024-05-31T18:39:12.435774Z","id":"CVE-2024-27435","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"problemTypes":[{"descriptions":[{"type":"CWE","lang":"en","description":"CWE-noinfo Not enough information"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2024-11-06T16:36:56.843Z"}},{"title":"CVE Program Container","references":[{"url":"https://git.kernel.org/stable/c/149afee5c7418ec5db9d7387b9c9a5c1eb7ea2a8","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/ff2f90f88d78559802466ad1c84ac5bda4416b3a","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/6851778504cdb49431809b4ba061903d5f592c96","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/262da920896e2f2ab0e3947d9dbee0aa09045818","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/de105068fead55ed5c07ade75e9c8e7f86a00d1d","tags":["x_transferred"]}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2024-08-02T00:34:52.327Z"}}]}}}