{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64496", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.792Z", "datePublished": "2026-07-25T08:51:53.194Z", "dateUpdated": "2026-08-17T04:56:44.840Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:56:44.840Z" }, "descriptions": [ { "lang": "en", "value": "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." } ], "metrics": [ { "cvssV3_1": { "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" }, "scenarios": [ { "lang": "en", "value": "AV:L - Exploitation uses local open(), ioctl(), and read() operations on /dev/iio:deviceX; no network-reachable path exists.\nAC:L - The attacker controls both racing threads and can predict the lowest available event fd, repeatedly race its installation, and stall the read using a userspace page fault.\nPR:L - The kernel path has no capability or authentication check; an ordinary user granted device-node access can invoke the vulnerable ioctl and read operations.\nUI:N - No victim action is required, and supported IIO drivers can generate events automatically through sensor interrupts.\nS:U - The vulnerability affects the kernel hosting the attacking process and does not inherently cross a VM, IOMMU, or separate security-authority boundary.\nC:H - The underflowed FIFO length permits an attacker-sized out-of-bounds read beyond the 256-byte event buffer, exposing adjacent kernel heap memory and potentially sensitive pointers or data.\nI:N - The path copies kernel data to userspace and corrupts only the FIFO read index; masked FIFO accesses provide no out-of-bounds write or control-flow modification primitive.\nA:H - An oversized read crossing the containing slab object triggers BUG() with hardened usercopy, causing a kernel oops or panic and allowing repeated denial of service." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/iio/industrialio-event.c" ], "versions": [ { "version": "b91accafbb1031b80d22ad83576877ff2f8b4774", "lessThan": "9dc84ba4be5bbeb29ee49efe6cea2cb32c461424", "status": "affected", "versionType": "git" }, { "version": "b91accafbb1031b80d22ad83576877ff2f8b4774", "lessThan": "d16a702ca7d29c0b7a9b509339d1b044a1cadb32", "status": "affected", "versionType": "git" }, { "version": "b91accafbb1031b80d22ad83576877ff2f8b4774", "lessThan": "a13ef1adbc62085b21b546b07b0be7e2fbf52150", "status": "affected", "versionType": "git" }, { "version": "b91accafbb1031b80d22ad83576877ff2f8b4774", "lessThan": "0d4a646d7f87ea3625fafe387043fddc6a2f5e7f", "status": "affected", "versionType": "git" }, { "version": "b91accafbb1031b80d22ad83576877ff2f8b4774", "lessThan": "72c6aa8e0d74eab91b8694cde97dec088c248fee", "status": "affected", "versionType": "git" }, { "version": "b91accafbb1031b80d22ad83576877ff2f8b4774", "lessThan": "9edefd4c56bee3fe331e0355d1f10a533134999d", "status": "affected", "versionType": "git" }, { "version": "b91accafbb1031b80d22ad83576877ff2f8b4774", "lessThan": "f187dc5a4c4846ffa07d9bda6e760837ed005574", "status": "affected", "versionType": "git" }, { "version": "b91accafbb1031b80d22ad83576877ff2f8b4774", "lessThan": "af791d295737ea6b6ff2c8d8488462a49c14af01", "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-event.c" ], "versions": [ { "version": "3.15", "status": "affected" }, { "version": "0", "lessThan": "3.15", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.261", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.212", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.96", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.39", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.4", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "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": "3.15", "versionEndExcluding": "5.10.261" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.15", "versionEndExcluding": "5.15.212" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.15", "versionEndExcluding": "6.1.178" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.15", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.15", "versionEndExcluding": "6.12.96" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.15", "versionEndExcluding": "6.18.39" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.15", "versionEndExcluding": "7.1.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.15", "versionEndExcluding": "7.2" } ] } ] } ], "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" } } } }