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CVE-2026-74690 (GCVE-0-2026-74690)

Vulnerability from cvelistv5 – Published: 2026-08-22 15:32 – Updated: 2026-08-25 05:41
VLAI
Title
s390/ism: Fix UAF of sba and ieq during ism_dev_exit()
Summary
In the Linux kernel, the following vulnerability has been resolved: s390/ism: Fix UAF of sba and ieq during ism_dev_exit() A ism interrupt handler can be active in parallel with ism_dev_exit(), accessing freed data structures. No new interrupts will be generated after unregister_ieq(). Drain ongoing interrupt handlers by free_irq(), before freeing ism data structures.
Severity
8.4 (High)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 684b89bc39ce4f204b1a2b180f39f2eb36a6b695 , < fc3021284050ecb3bba8a7851340cedcb5037928 (git)
Affected: 684b89bc39ce4f204b1a2b180f39f2eb36a6b695 , < 774394d27930ec4cf4cb3eed8ab6a4d20cb2430a (git)
Affected: 684b89bc39ce4f204b1a2b180f39f2eb36a6b695 , < b1896543ce59c4258625a35cf41e23a9a1f80ea2 (git)
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Linux Linux Affected: 4.19
Unaffected: 0 , < 4.19 (semver)
Unaffected: 6.18.45 , ≤ 6.18.* (semver)
Unaffected: 7.1.9 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/s390/net/ism_drv.c"
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          "vendor": "Linux",
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              "status": "affected",
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              "version": "0",
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              "versionType": "semver"
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              "negate": false,
              "operator": "OR"
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        }
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      "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": {
            "baseScore": 8.4,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "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."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-25T05:41:35.158Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/fc3021284050ecb3bba8a7851340cedcb5037928"
        },
        {
          "url": "https://git.kernel.org/stable/c/774394d27930ec4cf4cb3eed8ab6a4d20cb2430a"
        },
        {
          "url": "https://git.kernel.org/stable/c/b1896543ce59c4258625a35cf41e23a9a1f80ea2"
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74690",
    "datePublished": "2026-08-22T15:32:54.650Z",
    "dateReserved": "2026-08-15T05:44:03.926Z",
    "dateUpdated": "2026-08-25T05:41:35.158Z",
    "state": "PUBLISHED"
  },
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  "vulnerability-lookup:meta": {
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      "date": "2026-09-16",
      "epss": "0.0014",
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    },
    "microsoft_vex": {
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      "id": "msrc_CVE-2026-74690",
      "initial_release_date": "2026-08-24T01:11:13.000Z",
      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "s390/ism: Fix UAF of sba and ieq during ism_dev_exit()",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-74690.json",
      "version": "2"
    },
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    "suse_vex": {
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      "cve": "CVE-2026-74690",
      "id": "CVE-2026-74690",
      "initial_release_date": "2026-08-23T00:04:32Z",
      "product_status:known_affected": "351",
      "product_status:known_not_affected": "6",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-74690",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-74690.json",
      "version": "6"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.