{"api_version":"1","generated_at":"2026-08-02T14:53:18+00:00","cve":"CVE-2026-64496","urls":{"html":"https://cve.report/CVE-2026-64496","api":"https://cve.report/api/cve/CVE-2026-64496.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-64496","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64496"},"summary":{"title":"iio: event: Fix event FIFO reset race","description":"In the Linux kernel, the following vulnerability has been resolved:\n\niio: event: Fix event FIFO reset race\n\n`iio_event_getfd()` creates the event file descriptor with\n`anon_inode_getfd()`, which allocates a new fd, creates the anonymous\nfile and installs it in the process fd table before returning to the\ncaller.\n\nThe IIO code resets the event FIFO after `anon_inode_getfd()` has returned,\nbut before `IIO_GET_EVENT_FD_IOCTL` has copied the fd number to userspace.\nBut since fd tables are shared between threads, another thread can guess\nthe newly allocated fd number and issue a `read()` on it as soon as the fd\nhas been installed.\n\nThis means the `kfifo_to_user()` in `iio_event_chrdev_read()` can run in\nparallel with the `kfifo_reset_out()` in `iio_event_getfd()`.\n\nThe kfifo documentation says that `kfifo_reset_out()` is only safe when it\nis called from the reader thread and there is only one concurrent reader.\nOtherwise it is dangerous and must be handled in the same way as\n`kfifo_reset()`.\n\nIf that happens, `kfifo_to_user()` can advance the FIFO `out` index based\non state from before the reset, after the reset has already moved the `out`\nindex to the current `in` index. That can leave the FIFO with an `out`\nindex past the `in` index. A later `read()` can then see an underflowed\nFIFO length and copy more data than the event FIFO buffer contains. This\ncan result in an out-of-bounds read and leak adjacent kernel memory to\nuserspace.\n\nMove the FIFO reset before `anon_inode_getfd()`. At that point the event fd is\nmarked busy, but the new fd has not been installed yet, so userspace cannot\naccess it while the FIFO is reset.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-25 10:17:35","updated_at":"2026-07-27 05:16:54"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.1","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","baseScore":7.1,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"NONE","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.1","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","data":{"baseScore":7.1,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/a13ef1adbc62085b21b546b07b0be7e2fbf52150","name":"https://git.kernel.org/stable/c/a13ef1adbc62085b21b546b07b0be7e2fbf52150","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d16a702ca7d29c0b7a9b509339d1b044a1cadb32","name":"https://git.kernel.org/stable/c/d16a702ca7d29c0b7a9b509339d1b044a1cadb32","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0d4a646d7f87ea3625fafe387043fddc6a2f5e7f","name":"https://git.kernel.org/stable/c/0d4a646d7f87ea3625fafe387043fddc6a2f5e7f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f187dc5a4c4846ffa07d9bda6e760837ed005574","name":"https://git.kernel.org/stable/c/f187dc5a4c4846ffa07d9bda6e760837ed005574","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/72c6aa8e0d74eab91b8694cde97dec088c248fee","name":"https://git.kernel.org/stable/c/72c6aa8e0d74eab91b8694cde97dec088c248fee","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/af791d295737ea6b6ff2c8d8488462a49c14af01","name":"https://git.kernel.org/stable/c/af791d295737ea6b6ff2c8d8488462a49c14af01","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9dc84ba4be5bbeb29ee49efe6cea2cb32c461424","name":"https://git.kernel.org/stable/c/9dc84ba4be5bbeb29ee49efe6cea2cb32c461424","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9edefd4c56bee3fe331e0355d1f10a533134999d","name":"https://git.kernel.org/stable/c/9edefd4c56bee3fe331e0355d1f10a533134999d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-64496","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64496","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b91accafbb1031b80d22ad83576877ff2f8b4774 9dc84ba4be5bbeb29ee49efe6cea2cb32c461424 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b91accafbb1031b80d22ad83576877ff2f8b4774 d16a702ca7d29c0b7a9b509339d1b044a1cadb32 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b91accafbb1031b80d22ad83576877ff2f8b4774 a13ef1adbc62085b21b546b07b0be7e2fbf52150 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b91accafbb1031b80d22ad83576877ff2f8b4774 0d4a646d7f87ea3625fafe387043fddc6a2f5e7f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.212 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.178 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.145 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.96 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.39 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.4 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2-rc3 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"64496","cve":"CVE-2026-64496","epss":"0.001260000","percentile":"0.026850000","score_date":"2026-07-29","updated_at":"2026-07-30 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the Linux kernel, the following vulnerability has been resolved:\n\niio: event: Fix event FIFO reset race\n\n`iio_event_getfd()` creates the event file descriptor with\n`anon_inode_getfd()`, which allocates a new fd, creates the anonymous\nfile and installs it in the process fd table before returning to the\ncaller.\n\nThe IIO code resets the event FIFO after `anon_inode_getfd()` has returned,\nbut before `IIO_GET_EVENT_FD_IOCTL` has copied the fd number to userspace.\nBut since fd tables are shared between threads, another thread can guess\nthe newly allocated fd number and issue a `read()` on it as soon as the fd\nhas been installed.\n\nThis means the `kfifo_to_user()` in `iio_event_chrdev_read()` can run in\nparallel with the `kfifo_reset_out()` in `iio_event_getfd()`.\n\nThe kfifo documentation says that `kfifo_reset_out()` is only safe when it\nis called from the reader thread and there is only one concurrent reader.\nOtherwise it is dangerous and must be handled in the same way as\n`kfifo_reset()`.\n\nIf that happens, `kfifo_to_user()` can advance the FIFO `out` index based\non state from before the reset, after the reset has already moved the `out`\nindex to the current `in` index. That can leave the FIFO with an `out`\nindex past the `in` index. A later `read()` can then see an underflowed\nFIFO length and copy more data than the event FIFO buffer contains. This\ncan result in an out-of-bounds read and leak adjacent kernel memory to\nuserspace.\n\nMove the FIFO reset before `anon_inode_getfd()`. At that point the event fd is\nmarked busy, but the new fd has not been installed yet, so userspace cannot\naccess it while the FIFO is reset."}],"metrics":[{"cvssV3_1":{"baseScore":7.1,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","version":"3.1"}}],"providerMetadata":{"dateUpdated":"2026-07-27T05:01:29.899Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/9dc84ba4be5bbeb29ee49efe6cea2cb32c461424"},{"url":"https://git.kernel.org/stable/c/d16a702ca7d29c0b7a9b509339d1b044a1cadb32"},{"url":"https://git.kernel.org/stable/c/a13ef1adbc62085b21b546b07b0be7e2fbf52150"},{"url":"https://git.kernel.org/stable/c/0d4a646d7f87ea3625fafe387043fddc6a2f5e7f"},{"url":"https://git.kernel.org/stable/c/72c6aa8e0d74eab91b8694cde97dec088c248fee"},{"url":"https://git.kernel.org/stable/c/9edefd4c56bee3fe331e0355d1f10a533134999d"},{"url":"https://git.kernel.org/stable/c/f187dc5a4c4846ffa07d9bda6e760837ed005574"},{"url":"https://git.kernel.org/stable/c/af791d295737ea6b6ff2c8d8488462a49c14af01"}],"title":"iio: event: Fix event FIFO reset race","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-64496","datePublished":"2026-07-25T08:51:53.194Z","dateReserved":"2026-07-19T15:36:31.792Z","dateUpdated":"2026-07-27T05:01:29.899Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-25 10:17:35","lastModifiedDate":"2026-07-27 05:16:54","problem_types":[],"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:N/A:H","baseScore":7.1,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":5.2}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"64496","Ordinal":"1","Title":"iio: event: Fix event FIFO reset race","CVE":"CVE-2026-64496","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"64496","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\niio: event: Fix event FIFO reset race\n\n`iio_event_getfd()` creates the event file descriptor with\n`anon_inode_getfd()`, which allocates a new fd, creates the anonymous\nfile and installs it in the process fd table before returning to the\ncaller.\n\nThe IIO code resets the event FIFO after `anon_inode_getfd()` has returned,\nbut before `IIO_GET_EVENT_FD_IOCTL` has copied the fd number to userspace.\nBut since fd tables are shared between threads, another thread can guess\nthe newly allocated fd number and issue a `read()` on it as soon as the fd\nhas been installed.\n\nThis means the `kfifo_to_user()` in `iio_event_chrdev_read()` can run in\nparallel with the `kfifo_reset_out()` in `iio_event_getfd()`.\n\nThe kfifo documentation says that `kfifo_reset_out()` is only safe when it\nis called from the reader thread and there is only one concurrent reader.\nOtherwise it is dangerous and must be handled in the same way as\n`kfifo_reset()`.\n\nIf that happens, `kfifo_to_user()` can advance the FIFO `out` index based\non state from before the reset, after the reset has already moved the `out`\nindex to the current `in` index. That can leave the FIFO with an `out`\nindex past the `in` index. A later `read()` can then see an underflowed\nFIFO length and copy more data than the event FIFO buffer contains. This\ncan result in an out-of-bounds read and leak adjacent kernel memory to\nuserspace.\n\nMove the FIFO reset before `anon_inode_getfd()`. At that point the event fd is\nmarked busy, but the new fd has not been installed yet, so userspace cannot\naccess it while the FIFO is reset.","Type":"Description","Title":"iio: event: Fix event FIFO reset race"}]}}}