{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-63929", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T07:54:57.021Z", "datePublished": "2026-07-19T14:55:29.309Z", "dateUpdated": "2026-07-19T14:55:29.309Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-07-19T14:55:29.309Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\niio: buffer: Fix DMA fence leak in iio_buffer_enqueue_dmabuf()\n\niio_buffer_enqueue_dmabuf() allocates a struct iio_dma_fence (104 bytes,\nkmalloc-128) via kmalloc_obj()+dma_fence_init(), which sets the initial\nkref to 1. It then calls dma_resv_add_fence() which takes a second\nreference (kref=2), and stores a raw pointer in block->fence.\n\nOn the success path the function returns without calling dma_fence_put()\nto release the initial reference, so every buffer enqueue permanently\nleaks one kmalloc-128 allocation.\n\nThe iio_buffer_cleanup() work item only releases the temporary reference\ntaken during completion signalling by iio_buffer_signal_dmabuf_done();\nthe initial reference from dma_fence_init() is never released.\n\nWith four iio_rwdev instances at 240kHz and 512 samples per buffer,\nthis produces ~1875 kmalloc-128 allocations per second matching the\nobserved slab growth exactly. A test with ftrace confirmed that the\ndma_fence_destroy event was never triggered.\n\nFix by calling dma_fence_put() after dma_resv_add_fence(), transferring\nownership of the fence to the DMA reservation object. The DMA fence then\ngets properly discarded after being signalled."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/iio/industrialio-buffer.c"], "versions": [{"version": "3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f", "lessThan": "9678aeed8b77d495a417dd057d479f3733094019", "status": "affected", "versionType": "git"}, {"version": "3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f", "lessThan": "3412a95afaa5d3262008dfc34f3c7be33d8151dc", "status": "affected", "versionType": "git"}, {"version": "3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f", "lessThan": "96cdeaba6a008503455b78a9641c05c2a886a7ec", "status": "affected", "versionType": "git"}, {"version": "3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f", "lessThan": "a093999355084bdbfe6e97f1dd232e58a1525f0b", "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/iio/industrialio-buffer.c"], "versions": [{"version": "6.11", "status": "affected"}, {"version": "0", "lessThan": "6.11", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.93", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.35", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.0.12", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1", "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": "6.11", "versionEndExcluding": "6.12.93"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "6.18.35"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "7.0.12"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.11", "versionEndExcluding": "7.1"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/9678aeed8b77d495a417dd057d479f3733094019"}, {"url": "https://git.kernel.org/stable/c/3412a95afaa5d3262008dfc34f3c7be33d8151dc"}, {"url": "https://git.kernel.org/stable/c/96cdeaba6a008503455b78a9641c05c2a886a7ec"}, {"url": "https://git.kernel.org/stable/c/a093999355084bdbfe6e97f1dd232e58a1525f0b"}], "title": "iio: buffer: Fix DMA fence leak in iio_buffer_enqueue_dmabuf()", "x_generator": {"engine": "bippy-1.2.0"}}}}

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{"bugzilla": {"description": "kernel: iio: buffer: Fix DMA fence leak in iio_buffer_enqueue_dmabuf()", "id": "2502456", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2502456"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.5", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-772", "details": ["In the Linux kernel, the following vulnerability has been resolved:\niio: buffer: Fix DMA fence leak in iio_buffer_enqueue_dmabuf()\niio_buffer_enqueue_dmabuf() allocates a struct iio_dma_fence (104 bytes,\nkmalloc-128) via kmalloc_obj()+dma_fence_init(), which sets the initial\nkref to 1. It then calls dma_resv_add_fence() which takes a second\nreference (kref=2), and stores a raw pointer in block->fence.\nOn the success path the function returns without calling dma_fence_put()\nto release the initial reference, so every buffer enqueue permanently\nleaks one kmalloc-128 allocation.\nThe iio_buffer_cleanup() work item only releases the temporary reference\ntaken during completion signalling by iio_buffer_signal_dmabuf_done();\nthe initial reference from dma_fence_init() is never released.\nWith four iio_rwdev instances at 240kHz and 512 samples per buffer,\nthis produces ~1875 kmalloc-128 allocations per second matching the\nobserved slab growth exactly. A test with ftrace confirmed that the\ndma_fence_destroy event was never triggered.\nFix by calling dma_fence_put() after dma_resv_add_fence(), transferring\nownership of the fence to the DMA reservation object. The DMA fence then\ngets properly discarded after being signalled.", "A flaw was found in the Linux kernel's Industrial I/O (iio) buffer component. The `iio_buffer_enqueue_dmabuf()` function, responsible for managing Direct Memory Access (DMA) buffers, fails to properly release a memory reference. This oversight results in a continuous memory leak, where small blocks of memory are permanently allocated but never freed. Over time, this can lead to memory exhaustion and a Denial of Service (DoS) condition, making the system unstable or unresponsive."], "name": "CVE-2026-63929", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-07-19T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-63929\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-63929\nhttps://lore.kernel.org/linux-cve-announce/2026071950-CVE-2026-63929-42fb@gregkh/T"], "threat_severity": "Low"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f,9678aeed8b77d495a417dd057d479f3733094019)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f,3412a95afaa5d3262008dfc34f3c7be33d8151dc)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f,96cdeaba6a008503455b78a9641c05c2a886a7ec)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f,a093999355084bdbfe6e97f1dd232e58a1525f0b)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "6.11"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,6.11)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.93,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.35,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.0.12,7.1.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.1,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-07-21T14:45:02.195473+00:00", "updated": "2026-07-22T18:30:03.537353+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"], "weaknesses": ["CWE-401"]}