CVE-2026-74734 (GCVE-0-2026-74734)

Vulnerability from cvelistv5 – Published: 2026-08-26 14:36 – Updated: 2026-08-26 14:36
VLAI
Title
firewire: ohci: fix NULL pointer dereference in ar_context_release
Summary
In the Linux kernel, the following vulnerability has been resolved: firewire: ohci: fix NULL pointer dereference in ar_context_release During the error handling path of the driver's probe function, a NULL pointer dereference can occur in ar_context_release(). When pci_probe() fails early (e.g., if pcim_enable_device() or MMIO mapping fails), the devres cleanup mechanism invokes release_ohci(). This function unconditionally calls ar_context_release() to clean up the asynchronous receive contexts. However, if ar_context_init() was not yet called, ctx->ohci remains NULL (as the fw_ohci structure is zero-initialized by devres_alloc()). ar_context_release() immediately dereferences ctx->ohci to get the dev pointer before checking if the context was actually initialized, leading to a crash: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] RIP: 0010:ar_context_release+0x3f/0x380 drivers/firewire/ohci.c:543 Call Trace: release_ohci+0x3f/0x60 drivers/firewire/ohci.c:3567 release_nodes drivers/base/devres.c:546 [inline] devres_release_all+0x1a8/0x260 drivers/base/devres.c:576 device_unbind_cleanup drivers/base/dd.c:597 [inline] really_probe+0x451/0xae0 drivers/base/dd.c:772 To fix this, move the assignment of the dev pointer after the !ctx->buffer check. If ctx->buffer is NULL, it indicates that the context was never successfully initialized and there is nothing to release, safely avoiding the dereference of the uninitialized ctx->ohci pointer.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 5716e58aecdd4f7225c2e46ce903a839fc54f22f , < ed5470771c7ed7f959230c4697f316af83426a90 (git)
Affected: 5716e58aecdd4f7225c2e46ce903a839fc54f22f , < 7d228ba43279de2d191f25e139fad166409c2c06 (git)
Affected: 5716e58aecdd4f7225c2e46ce903a839fc54f22f , < 42d217add8d80d6e7d9f58f80d11ea9b07ea113e (git)
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Linux Linux Affected: 6.5
Unaffected: 0 , < 6.5 (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": {
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/firewire/ohci.c"
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              "versionType": "semver"
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              "versionType": "semver"
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              "negate": false,
              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfirewire: ohci: fix NULL pointer dereference in ar_context_release\n\nDuring the error handling path of the driver\u0027s probe function, a NULL\npointer dereference can occur in ar_context_release().\n\nWhen pci_probe() fails early (e.g., if pcim_enable_device() or MMIO mapping\nfails), the devres cleanup mechanism invokes release_ohci(). This function\nunconditionally calls ar_context_release() to clean up the asynchronous\nreceive contexts. However, if ar_context_init() was not yet called,\nctx-\u003eohci remains NULL (as the fw_ohci structure is zero-initialized by\ndevres_alloc()).\n\nar_context_release() immediately dereferences ctx-\u003eohci to get the dev\npointer before checking if the context was actually initialized, leading to\na crash:\n\nOops: general protection fault, probably for non-canonical address\n0xdffffc0000000001: 0000 [#1] SMP KASAN NOPTI\nKASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]\nRIP: 0010:ar_context_release+0x3f/0x380 drivers/firewire/ohci.c:543\nCall Trace:\n release_ohci+0x3f/0x60 drivers/firewire/ohci.c:3567\n release_nodes drivers/base/devres.c:546 [inline]\n devres_release_all+0x1a8/0x260 drivers/base/devres.c:576\n device_unbind_cleanup drivers/base/dd.c:597 [inline]\n really_probe+0x451/0xae0 drivers/base/dd.c:772\n\nTo fix this, move the assignment of the dev pointer after the !ctx-\u003ebuffer\ncheck. If ctx-\u003ebuffer is NULL, it indicates that the context was never\nsuccessfully initialized and there is nothing to release, safely avoiding\nthe dereference of the uninitialized ctx-\u003eohci pointer."
        }
      ],
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        "dateUpdated": "2026-08-26T14:36:48.753Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/ed5470771c7ed7f959230c4697f316af83426a90"
        },
        {
          "url": "https://git.kernel.org/stable/c/7d228ba43279de2d191f25e139fad166409c2c06"
        },
        {
          "url": "https://git.kernel.org/stable/c/42d217add8d80d6e7d9f58f80d11ea9b07ea113e"
        }
      ],
      "title": "firewire: ohci: fix NULL pointer dereference in ar_context_release",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74734",
    "datePublished": "2026-08-26T14:36:48.753Z",
    "dateReserved": "2026-08-15T05:44:03.930Z",
    "dateUpdated": "2026-08-26T14:36:48.753Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-74734",
      "date": "2026-09-01",
      "epss": "0.00173",
      "percentile": "0.06867"
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    "nvd": "{\"cve\":{\"id\":\"CVE-2026-74734\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-26T15:16:51.927\",\"lastModified\":\"2026-08-26T15:16:51.927\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nfirewire: ohci: fix NULL pointer dereference in ar_context_release\\n\\nDuring the error handling path of the driver\u0027s probe function, a NULL\\npointer dereference can occur in ar_context_release().\\n\\nWhen pci_probe() fails early (e.g., if pcim_enable_device() or MMIO mapping\\nfails), the devres cleanup mechanism invokes release_ohci(). This function\\nunconditionally calls ar_context_release() to clean up the asynchronous\\nreceive contexts. However, if ar_context_init() was not yet called,\\nctx-\u003eohci remains NULL (as the fw_ohci structure is zero-initialized by\\ndevres_alloc()).\\n\\nar_context_release() immediately dereferences ctx-\u003eohci to get the dev\\npointer before checking if the context was actually initialized, leading to\\na crash:\\n\\nOops: general protection fault, probably for non-canonical address\\n0xdffffc0000000001: 0000 [#1] SMP KASAN NOPTI\\nKASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]\\nRIP: 0010:ar_context_release+0x3f/0x380 drivers/firewire/ohci.c:543\\nCall Trace:\\n release_ohci+0x3f/0x60 drivers/firewire/ohci.c:3567\\n release_nodes drivers/base/devres.c:546 [inline]\\n devres_release_all+0x1a8/0x260 drivers/base/devres.c:576\\n device_unbind_cleanup drivers/base/dd.c:597 [inline]\\n really_probe+0x451/0xae0 drivers/base/dd.c:772\\n\\nTo fix this, move the assignment of the dev pointer after the !ctx-\u003ebuffer\\ncheck. If ctx-\u003ebuffer is NULL, it indicates that the context was never\\nsuccessfully initialized and there is nothing to release, safely avoiding\\nthe dereference of the uninitialized ctx-\u003eohci pointer.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"drivers/firewire/ohci.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"5716e58aecdd4f7225c2e46ce903a839fc54f22f\",\"lessThan\":\"ed5470771c7ed7f959230c4697f316af83426a90\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"5716e58aecdd4f7225c2e46ce903a839fc54f22f\",\"lessThan\":\"7d228ba43279de2d191f25e139fad166409c2c06\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"5716e58aecdd4f7225c2e46ce903a839fc54f22f\",\"lessThan\":\"42d217add8d80d6e7d9f58f80d11ea9b07ea113e\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"drivers/firewire/ohci.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.5\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.5\",\"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\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/42d217add8d80d6e7d9f58f80d11ea9b07ea113e\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/7d228ba43279de2d191f25e139fad166409c2c06\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ed5470771c7ed7f959230c4697f316af83426a90\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2026-08-27T06:15:40+00:00",
      "cve": "CVE-2026-74734",
      "id": "CVE-2026-74734",
      "initial_release_date": "2026-08-26T00:00:00+00:00",
      "product_status:known_affected": "14",
      "product_status:known_not_affected": "260",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: firewire: ohci: fix NULL pointer dereference in ar_context_release",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74734.json",
      "version": "3"
    }
  }
}



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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
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