{"id":"CVE-2026-64328","state":"PUBLISHED","title":"usb: gadget: f_fs: Fix DMA fence leak","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_fs: Fix DMA fence leak\n\nIn ffs_dmabuf_transfer(), a ffs_dma_fence object is kmalloc'd, with the\nunderlying dma_fence later initialized by dma_fence_init(), which sets\nits kref counter to 1. Then, dma_resv_add_fence() gets a second\nreference, and a pointer to the ffs_dma_fence is passed as the\nusb_request's \"context\" field.\n\nThe dma-resv mechanism will manage the second reference, but the first\nreference is never properly released; the ffs_dmabuf_cleanup() function\ndecreases the reference count, but only to balance with the reference\ngrab in ffs_dmabuf_signal_done().\n\nThe code will then slowly leak memory as more ffs_dma_fence objects are\ncreated without being ever freed.\n\nAddress this issue by transferring ownership of the fence to the DMA\nreservation object, by calling dma_fence_put() right after\ndma_resv_add_fence(). The ffs_dma_fence then gets properly discarded\nafter being signalled.","publishedAt":"2026-07-25T08:49:56.340Z","updatedAt":"2026-08-17T04:53:30.558Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"7b07a2a7ca02a20124b552be96c5a56910795488","status":"affected","lessThan":"b7475b2dce5e121e687280ba5732ccefe77ffd2f","versionType":"git"},{"version":"7b07a2a7ca02a20124b552be96c5a56910795488","status":"affected","lessThan":"e086c16962a1b0142e2675610e9c06fcfcd4c3a8","versionType":"git"},{"version":"7b07a2a7ca02a20124b552be96c5a56910795488","status":"affected","lessThan":"0cae3d6109427c455bad0a18dfb3e2a91657e38a","versionType":"git"},{"version":"7b07a2a7ca02a20124b552be96c5a56910795488","status":"affected","lessThan":"baa6b6068a3f2bf2ed525a1cb37975905dadc658","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/usb/gadget/function/f_fs.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.9","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.9","versionType":"semver"},{"version":"6.12.96","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.39","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.4","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/usb/gadget/function/f_fs.c"]}],"references":["https://git.kernel.org/stable/c/b7475b2dce5e121e687280ba5732ccefe77ffd2f","https://git.kernel.org/stable/c/e086c16962a1b0142e2675610e9c06fcfcd4c3a8","https://git.kernel.org/stable/c/0cae3d6109427c455bad0a18dfb3e2a91657e38a","https://git.kernel.org/stable/c/baa6b6068a3f2bf2ed525a1cb37975905dadc658"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/64xxx/CVE-2026-64328.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64328","state":"PUBLISHED","datePublished":"2026-07-25T08:49:56.340Z","dateUpdated":"2026-08-17T04:53:30.558Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T15:36:31.780Z"},"containers":{"cna":{"title":"usb: gadget: f_fs: Fix DMA fence leak","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_fs: Fix DMA fence leak\n\nIn ffs_dmabuf_transfer(), a ffs_dma_fence object is kmalloc'd, with the\nunderlying dma_fence later initialized by dma_fence_init(), which sets\nits kref counter to 1. Then, dma_resv_add_fence() gets a second\nreference, and a pointer to the ffs_dma_fence is passed as the\nusb_request's \"context\" field.\n\nThe dma-resv mechanism will manage the second reference, but the first\nreference is never properly released; the ffs_dmabuf_cleanup() function\ndecreases the reference count, but only to balance with the reference\ngrab in ffs_dmabuf_signal_done().\n\nThe code will then slowly leak memory as more ffs_dma_fence objects are\ncreated without being ever freed.\n\nAddress this issue by transferring ownership of the fence to the DMA\nreservation object, by calling dma_fence_put() right after\ndma_resv_add_fence(). The ffs_dma_fence then gets properly discarded\nafter being signalled."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"7b07a2a7ca02a20124b552be96c5a56910795488","status":"affected","lessThan":"b7475b2dce5e121e687280ba5732ccefe77ffd2f","versionType":"git"},{"version":"7b07a2a7ca02a20124b552be96c5a56910795488","status":"affected","lessThan":"e086c16962a1b0142e2675610e9c06fcfcd4c3a8","versionType":"git"},{"version":"7b07a2a7ca02a20124b552be96c5a56910795488","status":"affected","lessThan":"0cae3d6109427c455bad0a18dfb3e2a91657e38a","versionType":"git"},{"version":"7b07a2a7ca02a20124b552be96c5a56910795488","status":"affected","lessThan":"baa6b6068a3f2bf2ed525a1cb37975905dadc658","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/usb/gadget/function/f_fs.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.9","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.9","versionType":"semver"},{"version":"6.12.96","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.39","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.4","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/usb/gadget/function/f_fs.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/b7475b2dce5e121e687280ba5732ccefe77ffd2f"},{"url":"https://git.kernel.org/stable/c/e086c16962a1b0142e2675610e9c06fcfcd4c3a8"},{"url":"https://git.kernel.org/stable/c/0cae3d6109427c455bad0a18dfb3e2a91657e38a"},{"url":"https://git.kernel.org/stable/c/baa6b6068a3f2bf2ed525a1cb37975905dadc658"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T04:53:30.558Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"6.12.96"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"6.18.39"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"7.1.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}