{"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":"2026-08-25T05:41:35.158Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-25T05:41:35.158Z"},"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":"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":"6.18.45","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":"6.18.45"},{"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/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"}}}}