CVE-2026-80556 (GCVE-0-2026-80556)

Vulnerability from cvelistv5 – Published: 2026-08-26 14:37 – Updated: 2026-08-27 05:01
VLAI
Title
mmc: atmel-mci: Fix use-after-free in atmci_remove due to race condition
Summary
In the Linux kernel, the following vulnerability has been resolved: mmc: atmel-mci: Fix use-after-free in atmci_remove due to race condition In atmci_probe, &host->bh_work is bound with atmci_work_func, and atmci_interrupt, atmci_timeout_timer and atmci_dma_complete can all queue this work on system_bh_wq. If we remove the module, atmci_remove makes cleanup and the memory allocated for host with devm_kzalloc() is released after the remove callback returns, while the work mentioned above may still be pending or running. The sequence of operations that may lead to a UAF bug is as follows: CPU0 CPU1 | atmci_interrupt | queue_work(system_bh_wq, | &host->bh_work) atmci_remove | atmci_cleanup_slot(...) | atmci_writel(host, ATMCI_IDR, ~0UL) | timer_delete_sync(&host->timer) | dma_release_channel(host->dma.chan) | free_irq(platform_get_irq(pdev, 0), host) | | atmci_work_func | // use host // devm resources released after | // remove returns, host is freed | | // use host (use-after-free) Fix it by canceling the work after all the sources that can schedule it (IRQ handler, timeout timer and DMA completion callback) have been stopped, and before proceeding with the remaining cleanup in atmci_remove.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 7d2be0749a59096a334c94dc48f43294193cb8ed , < 22aecf6c4721727a2f724ca0438bc7d4b609bf3f (git)
Affected: 7d2be0749a59096a334c94dc48f43294193cb8ed , < b5060ff2f5460795a3e9f7cdf5052aa42f96ff81 (git)
Affected: 7d2be0749a59096a334c94dc48f43294193cb8ed , < 7599a73ff66d195a908f5d88b427933a9fb1c02a (git)
Affected: 7d2be0749a59096a334c94dc48f43294193cb8ed , < c125ee35a49a0518521b52b27631eef061b8719a (git)
guessed Create a notification for this product.
Linux Linux Affected: 2.6.27
Unaffected: 0 , < 2.6.27 (semver)
Unaffected: 6.12.105 , ≤ 6.12.* (semver)
Unaffected: 6.18.46 , ≤ 6.18.* (semver)
Unaffected: 7.1.10 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/mmc/host/atmel-mci.c"
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              "versionType": "semver"
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              "versionType": "semver"
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                  "vulnerable": true
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmmc: atmel-mci: Fix use-after-free in atmci_remove due to race condition\n\nIn atmci_probe, \u0026host-\u003ebh_work is bound with atmci_work_func, and\natmci_interrupt, atmci_timeout_timer and atmci_dma_complete can all\nqueue this work on system_bh_wq.\n\nIf we remove the module, atmci_remove makes cleanup and the memory\nallocated for host with devm_kzalloc() is released after the remove\ncallback returns, while the work mentioned above may still be pending\nor running. The sequence of operations that may lead to a UAF bug is\nas follows:\n\nCPU0                                      CPU1\n\n                                          | atmci_interrupt\n                                          | queue_work(system_bh_wq,\n                                          |            \u0026host-\u003ebh_work)\natmci_remove                              |\natmci_cleanup_slot(...)                   |\natmci_writel(host, ATMCI_IDR, ~0UL)       |\ntimer_delete_sync(\u0026host-\u003etimer)           |\ndma_release_channel(host-\u003edma.chan)       |\nfree_irq(platform_get_irq(pdev, 0), host) |\n                                          | atmci_work_func\n                                          | // use host\n// devm resources released after          |\n// remove returns, host is freed          |\n                                          | // use host (use-after-free)\n\nFix it by canceling the work after all the sources that can schedule\nit (IRQ handler, timeout timer and DMA completion callback) have been\nstopped, and before proceeding with the remaining cleanup in\natmci_remove."
        }
      ],
      "metrics": [
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            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
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              "value": "AV:L - The UAF is in atmci_remove() platform-driver teardown (rmmod/sysfs unbind) while atmci_work_func() runs from IRQ/DMA/timer-driven work queued via local /dev/mmcblk* block I/O; there is no network, Bluetooth, or remote protocol path into this driver.\nAC:L - This is a classic removal-vs-workqueue race where the attacker controls both sides: concurrent mmcblk read/write (or SDIO traffic) schedules bh_work via atmci_interrupt/atmci_dma_complete/atmci_timeout_timer while timing driver unbind/rmmod, and can retry rapidly to win reliably.\nPR:L - Per CNA driver-removal UAF precedent, an unprivileged local user with /dev/mmcblk* access can drive the IRQ/DMA/timer side via block I/O while teardown occurs (admin unbind, rmmod, or automated reload during maintenance/reboot); init-namespace root is not the minimum privilege bar.\nUI:N - No victim interaction is required; the attacker performs mmcblk I/O themselves (or sustains SDIO/MMC activity) and coordinates or piggybacks on driver removal without needing another user to mount media or click anything.\nS:U - Impact is kernel heap corruption and privilege escalation within the same kernel security boundary on the Atmel/Microchip embedded host; this is not a VM escape, IOMMU bypass, or cross-authority sandbox breakout.\nC:H - atmci_work_func() dereferences the freed atmel_mci host (locks, mrq/data pointers, MMIO via host-\u003eregs); this kernel heap UAF enables arbitrary read primitives through controlled reuse of the freed structure.\nI:H - The UAF work handler performs MMIO writes (atmci_writel), manipulates mmc_request state, and invokes stop_transfer callbacks on attacker-influenced freed memory, enabling heap spraying and arbitrary kernel write/control-flow hijack.\nA:H - Use-after-free in atmci_work_func() during driver removal can cause immediate kernel oops/panic from dereferencing freed host memory, and successful exploitation can crash or hang the system even when not leveraged for code execution."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-27T05:01:44.585Z",
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        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/b5060ff2f5460795a3e9f7cdf5052aa42f96ff81"
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        {
          "url": "https://git.kernel.org/stable/c/c125ee35a49a0518521b52b27631eef061b8719a"
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-80556",
    "datePublished": "2026-08-26T14:37:23.573Z",
    "dateReserved": "2026-08-26T14:34:25.767Z",
    "dateUpdated": "2026-08-27T05:01:44.585Z",
    "state": "PUBLISHED"
  },
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      "date": "2026-09-01",
      "epss": "0.00125",
      "percentile": "0.02475"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-80556\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-26T15:17:10.253\",\"lastModified\":\"2026-08-27T06:17:39.387\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nmmc: atmel-mci: Fix use-after-free in atmci_remove due to race condition\\n\\nIn atmci_probe, \u0026host-\u003ebh_work is bound with atmci_work_func, and\\natmci_interrupt, atmci_timeout_timer and atmci_dma_complete can all\\nqueue this work on system_bh_wq.\\n\\nIf we remove the module, atmci_remove makes cleanup and the memory\\nallocated for host with devm_kzalloc() is released after the remove\\ncallback returns, while the work mentioned above may still be pending\\nor running. The sequence of operations that may lead to a UAF bug is\\nas follows:\\n\\nCPU0                                      CPU1\\n\\n                                          | atmci_interrupt\\n                                          | queue_work(system_bh_wq,\\n                                          |            \u0026host-\u003ebh_work)\\natmci_remove                              |\\natmci_cleanup_slot(...)                   |\\natmci_writel(host, ATMCI_IDR, ~0UL)       |\\ntimer_delete_sync(\u0026host-\u003etimer)           |\\ndma_release_channel(host-\u003edma.chan)       |\\nfree_irq(platform_get_irq(pdev, 0), host) |\\n                                          | atmci_work_func\\n                                          | // use host\\n// devm resources released after          |\\n// remove returns, host is freed          |\\n                                          | // use host (use-after-free)\\n\\nFix it by canceling the work after all the sources that can schedule\\nit (IRQ handler, timeout timer and DMA completion callback) have been\\nstopped, and before proceeding with the remaining cleanup in\\natmci_remove.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"drivers/mmc/host/atmel-mci.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"7d2be0749a59096a334c94dc48f43294193cb8ed\",\"lessThan\":\"22aecf6c4721727a2f724ca0438bc7d4b609bf3f\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"7d2be0749a59096a334c94dc48f43294193cb8ed\",\"lessThan\":\"b5060ff2f5460795a3e9f7cdf5052aa42f96ff81\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"7d2be0749a59096a334c94dc48f43294193cb8ed\",\"lessThan\":\"7599a73ff66d195a908f5d88b427933a9fb1c02a\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"7d2be0749a59096a334c94dc48f43294193cb8ed\",\"lessThan\":\"c125ee35a49a0518521b52b27631eef061b8719a\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"drivers/mmc/host/atmel-mci.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"2.6.27\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"2.6.27\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.105\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.46\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.10\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/22aecf6c4721727a2f724ca0438bc7d4b609bf3f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/7599a73ff66d195a908f5d88b427933a9fb1c02a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/b5060ff2f5460795a3e9f7cdf5052aa42f96ff81\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/c125ee35a49a0518521b52b27631eef061b8719a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-27T14:47:28+00:00",
      "cve": "CVE-2026-80556",
      "id": "CVE-2026-80556",
      "initial_release_date": "2026-08-26T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: mmc: atmel-mci: Fix use-after-free in atmci_remove due to race condition",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80556.json",
      "version": "3"
    }
  }
}



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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.
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  • 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.


Detection rules are retrieved from Rulezet.