{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-74690", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-08-15T05:44:03.926Z", "datePublished": "2026-08-22T15:32:54.650Z", "dateUpdated": "2026-10-21T12:46:09.495Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-21T12:46:09.495Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/ism: Fix UAF of sba and ieq during ism_dev_exit()\n\nA ism interrupt handler can be active in parallel with ism_dev_exit(),\naccessing freed data structures.\n\nNo new interrupts will be generated after unregister_ieq(). Drain ongoing\ninterrupt handlers by free_irq(), before freeing ism data structures." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.4, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The UAF is opened in ism_dev_exit() during local PCI/driver teardown (ism_remove on module unload, sysfs unbind, or hot-unplug); remote SMC-D peers can raise ISM IRQs but cannot alone reach the freeing path that creates the dangling sba/ieq pointers.\nAC:L - This is a classic UAF race where the attacker controls the IRQ side by sustaining SMC-D move_data/signal_event traffic (or timing rmmod/unbind) while teardown frees sba/ieq before free_irq(); no uncontrollable memory layout or rare config is required on IBM Z ISM deployments.\nPR:N - Privileged teardown opens the window, but the concurrent UAF dereference is performed by ISM IRQ handlers servicing SMC-D traffic from unprivileged local socket users or remote LPAR peers that need no credentials or capabilities on the victim LPAR, only SMC connectivity.\nUI:N - No victim interaction is required beyond normal automated ISM interrupt processing during driver removal; an attacker only needs to keep SMC-D sessions active (or flood them) while the ISM device is torn down during maintenance, module unload, or hot-unplug.\nS:U - Impact is kernel heap/DMA-coherent memory corruption and privilege escalation within the host/LPAR kernel; it does not cross a VM, hypervisor, IOMMU, or other security-authority boundary.\nC:H - ism_handle_irq() and ism_handle_event() read freed PAGE_SIZE sba and ieq DMA buffers (dmb_bits, dmbe_mask, event entries) after dma_free_coherent(), enabling sprayable slab reuse and arbitrary kernel memory disclosure per UAF guidance.\nI:H - The IRQ handler writes to freed sba fields (summary/event bits, dmbe_mask clears) and then calls dibs client handle_irq/handle_event with attacker-influenced SMC state, providing heap grooming and control-flow hijack primitives from the UAF.\nA:H - Concurrent access to freed sba/ieq in hardirq reliably causes kernel oops/panic during ISM teardown on active SMC-D workloads, and UAF guidance treats any ISM interrupt-time use-after-free as high availability impact even before full exploitation." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/s390/net/ism_drv.c" ], "versions": [ { "version": "684b89bc39ce4f204b1a2b180f39f2eb36a6b695", "lessThan": "950dac9e8c4e3cf68fa8c01f77d3ac3b7369c6a9", "status": "affected", "versionType": "git" }, { "version": "684b89bc39ce4f204b1a2b180f39f2eb36a6b695", "lessThan": "58803870ba0841e53b630a1290c6838b091dd128", "status": "affected", "versionType": "git" }, { "version": "684b89bc39ce4f204b1a2b180f39f2eb36a6b695", "lessThan": "fc3021284050ecb3bba8a7851340cedcb5037928", "status": "affected", "versionType": "git" }, { "version": "684b89bc39ce4f204b1a2b180f39f2eb36a6b695", "lessThan": "774394d27930ec4cf4cb3eed8ab6a4d20cb2430a", "status": "affected", "versionType": "git" }, { "version": "684b89bc39ce4f204b1a2b180f39f2eb36a6b695", "lessThan": "b1896543ce59c4258625a35cf41e23a9a1f80ea2", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/s390/net/ism_drv.c" ], "versions": [ { "version": "4.19", "status": "affected" }, { "version": "0", "lessThan": "4.19", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.160", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.114", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.45", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.9", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19", "versionEndExcluding": "6.6.160" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19", "versionEndExcluding": "6.12.114" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19", "versionEndExcluding": "6.18.45" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19", "versionEndExcluding": "7.1.9" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/950dac9e8c4e3cf68fa8c01f77d3ac3b7369c6a9" }, { "url": "https://git.kernel.org/stable/c/58803870ba0841e53b630a1290c6838b091dd128" }, { "url": "https://git.kernel.org/stable/c/fc3021284050ecb3bba8a7851340cedcb5037928" }, { "url": "https://git.kernel.org/stable/c/774394d27930ec4cf4cb3eed8ab6a4d20cb2430a" }, { "url": "https://git.kernel.org/stable/c/b1896543ce59c4258625a35cf41e23a9a1f80ea2" } ], "title": "s390/ism: Fix UAF of sba and ieq during ism_dev_exit()", "x_generator": { "engine": "bippy-1.2.0" } } } }