CVE-2026-63910 (GCVE-0-2026-63910)

Vulnerability from cvelistv5 – Published: 2026-07-19 14:55 – Updated: 2026-08-05 12:37
VLAI
Title
dma-buf: fix UAF in dma_buf_fd() tracepoint
Summary
In the Linux kernel, the following vulnerability has been resolved: dma-buf: fix UAF in dma_buf_fd() tracepoint Once FD_ADD() returns, the fd is live in the file descriptor table and a thread sharing that table can close() it before DMA_BUF_TRACE() runs. The close drops the last reference, __fput() frees the dma_buf, and the tracepoint then dereferences dmabuf to take dmabuf->name_lock -- slab-use-after-free. Split FD_ADD() back into get_unused_fd_flags() + fd_install() and emit the tracepoint between them. While the fdtable slot is reserved with a NULL file pointer, a racing close() returns -EBADF without entering __fput(), so the dma_buf stays alive across the trace. Same approach as commit 2d76319c4cbb ("dma-buf: fix UAF in dma_buf_put() tracepoint"). This undoes the FD_ADD() conversion done in commit 34dfce523c90 ("dma: convert dma_buf_fd() to FD_ADD()"); FD_ADD() has no place to hook the tracepoint safely.
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: 281a226314238e8adb08d11b765347687ffb38b9 , < b569f86e2f8dbf6f11d31d3de794d22e18098b23 (git)
Affected: 281a226314238e8adb08d11b765347687ffb38b9 , < ead6680f354f83966c796fc7f9463a3171789616 (git)
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Linux Linux Affected: 7.0
Unaffected: 0 , < 7.0 (semver)
Unaffected: 7.0.12 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/dma-buf/dma-buf.c"
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          "vendor": "Linux",
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              "versionType": "git"
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                  "versionStartIncluding": "7.0",
                  "vulnerable": true
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              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndma-buf: fix UAF in dma_buf_fd() tracepoint\n\nOnce FD_ADD() returns, the fd is live in the file descriptor table\nand a thread sharing that table can close() it before DMA_BUF_TRACE()\nruns. The close drops the last reference, __fput() frees the dma_buf,\nand the tracepoint then dereferences dmabuf to take dmabuf-\u003ename_lock\n-- slab-use-after-free.\n\nSplit FD_ADD() back into get_unused_fd_flags() + fd_install() and\nemit the tracepoint between them. While the fdtable slot is reserved\nwith a NULL file pointer, a racing close() returns -EBADF without\nentering __fput(), so the dma_buf stays alive across the trace. Same\napproach as commit 2d76319c4cbb (\"dma-buf: fix UAF in dma_buf_put()\ntracepoint\").\n\nThis undoes the FD_ADD() conversion done in commit 34dfce523c90\n(\"dma: convert dma_buf_fd() to FD_ADD()\"); FD_ADD() has no place to\nhook the tracepoint safely."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "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"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The UAF is reached only through local syscalls/ioctls (e.g. UDMABUF_CREATE, DMA_HEAP_IOCTL_ALLOC, DRM/videobuf2 buffer export) that call dma_buf_fd(); there is no network or physical-device entry point.\nAC:L - Exploitation requires a race between dma_buf_fd() and close() on a shared fd table, but the attacker controls both threads and can hammer the window concurrently; syzkaller demonstrated reliable triggering without conditions outside attacker control.\nPR:L - An unprivileged local user with access to dma-buf interfaces (udmabuf, dma_heap, DRM render node, or media devices) can reach dma_buf_fd(); syzbot confirmed unprivileged and user-namespace reachability without real root in the init namespace.\nUI:N - Exploitation is performed entirely by the attacker\u0027s own multi-threaded process issuing ioctls and close() calls; no action by a separate victim user is required.\nS:U - Impact is kernel memory corruption and privilege escalation within the same kernel security domain; this is standard local kernel compromise, not a VM escape or IOMMU/DMA boundary bypass.\nC:H - The bug is a slab use-after-free on struct dma_buf; the tracepoint dereferences freed memory (name_lock, exp_name, file fields), enabling controlled reuse of freed kmalloc-1k objects for arbitrary kernel memory disclosure.\nI:H - UAF on a kmalloc-1k kernel object with spinlock interaction provides heap corruption primitives that can be developed into arbitrary kernel writes and local privilege escalation.\nA:H - Winning the race causes a confirmed slab-use-after-free in dma_buf_fd() (KASAN/lockdep fault), which can panic or oops the kernel even when not fully exploited for code execution."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:37:04.026Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/b569f86e2f8dbf6f11d31d3de794d22e18098b23"
        },
        {
          "url": "https://git.kernel.org/stable/c/ead6680f354f83966c796fc7f9463a3171789616"
        }
      ],
      "title": "dma-buf: fix UAF in dma_buf_fd() tracepoint",
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        "engine": "bippy-1.2.0"
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-63910",
    "datePublished": "2026-07-19T14:55:15.770Z",
    "dateReserved": "2026-07-19T07:54:57.020Z",
    "dateUpdated": "2026-08-05T12:37:04.026Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-63910",
      "date": "2026-09-21",
      "epss": "0.00154",
      "percentile": "0.0492"
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            "affectedData": [
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                "product": "Linux",
                "programFiles": [
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                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndma-buf: fix UAF in dma_buf_fd() tracepoint\n\nOnce FD_ADD() returns, the fd is live in the file descriptor table\nand a thread sharing that table can close() it before DMA_BUF_TRACE()\nruns. The close drops the last reference, __fput() frees the dma_buf,\nand the tracepoint then dereferences dmabuf to take dmabuf-\u003ename_lock\n-- slab-use-after-free.\n\nSplit FD_ADD() back into get_unused_fd_flags() + fd_install() and\nemit the tracepoint between them. While the fdtable slot is reserved\nwith a NULL file pointer, a racing close() returns -EBADF without\nentering __fput(), so the dma_buf stays alive across the trace. Same\napproach as commit 2d76319c4cbb (\"dma-buf: fix UAF in dma_buf_put()\ntracepoint\").\n\nThis undoes the FD_ADD() conversion done in commit 34dfce523c90\n(\"dma: convert dma_buf_fd() to FD_ADD()\"); FD_ADD() has no place to\nhook the tracepoint safely."
          }
        ],
        "id": "CVE-2026-63910",
        "lastModified": "2026-07-27T17:44:23.777",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 1.8,
              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            }
          ]
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        "published": "2026-07-19T16:17:08.857",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/b569f86e2f8dbf6f11d31d3de794d22e18098b23"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/ead6680f354f83966c796fc7f9463a3171789616"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Awaiting Analysis"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-09-10T10:19:14+00:00",
      "cve": "CVE-2026-63910",
      "id": "CVE-2026-63910",
      "initial_release_date": "2026-07-19T00:00:00+00:00",
      "product_status:known_affected": "2",
      "product_status:known_not_affected": "272",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: dma-buf: fix UAF in dma_buf_fd() tracepoint",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63910.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-07-28T23:38:11Z",
      "cve": "CVE-2026-63910",
      "id": "CVE-2026-63910",
      "initial_release_date": "2026-07-21T13:03:45Z",
      "product_status:known_not_affected": "298",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-63910",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-63910.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.
  • 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.