{"id":"CVE-2026-64289","state":"PUBLISHED","title":"iommufd: Set upper bounds on cache invalidation entry_num and entry_len","description":"In the Linux kernel, the following vulnerability has been resolved:\n\niommufd: Set upper bounds on cache invalidation entry_num and entry_len\n\niommufd_hwpt_invalidate() takes a user-controlled entry_num and entry_len,\neach bounded only by U32_MAX. An entry_len beyond the kernel's struct size\nmakes the copy helper verify the extra bytes are zero, scanning that excess\nin one uninterruptible pass; a multi-gigabyte value over zeroed user memory\ntrips the soft-lockup watchdog.\n\nA large entry_num is the other half, driving the backend invalidation loop\nwith no reschedule. The VT-d nested handler, for one, copies each entry and\nflushes caches per iteration, pinning the CPU on a non-preemptible kernel.\n\nCap both in the ioctl. entry_len is held under PAGE_SIZE, above any request\nstruct, and entry_num under 1 << 19, the order of a hardware invalidation\nqueue and well beyond any real batch, bounding the per-call loop length.","publishedAt":"2026-07-25T08:49:29.434Z","updatedAt":"2026-08-17T04:52:45.289Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"8c6eabae3807e048b9f17733af5e20500fbf858c","status":"affected","lessThan":"d2bd041e0efaf7d81789779b135279d18b33d6d5","versionType":"git"},{"version":"8c6eabae3807e048b9f17733af5e20500fbf858c","status":"affected","lessThan":"32ca4aed2a66205b072fcfecabe220289a8149ff","versionType":"git"},{"version":"8c6eabae3807e048b9f17733af5e20500fbf858c","status":"affected","lessThan":"2c6381d90898089287e0a358f06f89f6b4b389f2","versionType":"git"},{"version":"8c6eabae3807e048b9f17733af5e20500fbf858c","status":"affected","lessThan":"4d70986002f2f3eaaed89124fb2522bded38b016","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/iommu/iommufd/hw_pagetable.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.8","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/iommu/iommufd/hw_pagetable.c"]}],"references":["https://git.kernel.org/stable/c/d2bd041e0efaf7d81789779b135279d18b33d6d5","https://git.kernel.org/stable/c/32ca4aed2a66205b072fcfecabe220289a8149ff","https://git.kernel.org/stable/c/2c6381d90898089287e0a358f06f89f6b4b389f2","https://git.kernel.org/stable/c/4d70986002f2f3eaaed89124fb2522bded38b016"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/64xxx/CVE-2026-64289.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64289","state":"PUBLISHED","datePublished":"2026-07-25T08:49:29.434Z","dateUpdated":"2026-08-17T04:52:45.289Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T15:36:31.778Z"},"containers":{"cna":{"title":"iommufd: Set upper bounds on cache invalidation entry_num and entry_len","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\niommufd: Set upper bounds on cache invalidation entry_num and entry_len\n\niommufd_hwpt_invalidate() takes a user-controlled entry_num and entry_len,\neach bounded only by U32_MAX. An entry_len beyond the kernel's struct size\nmakes the copy helper verify the extra bytes are zero, scanning that excess\nin one uninterruptible pass; a multi-gigabyte value over zeroed user memory\ntrips the soft-lockup watchdog.\n\nA large entry_num is the other half, driving the backend invalidation loop\nwith no reschedule. The VT-d nested handler, for one, copies each entry and\nflushes caches per iteration, pinning the CPU on a non-preemptible kernel.\n\nCap both in the ioctl. entry_len is held under PAGE_SIZE, above any request\nstruct, and entry_num under 1 << 19, the order of a hardware invalidation\nqueue and well beyond any real batch, bounding the per-call loop length."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"8c6eabae3807e048b9f17733af5e20500fbf858c","status":"affected","lessThan":"d2bd041e0efaf7d81789779b135279d18b33d6d5","versionType":"git"},{"version":"8c6eabae3807e048b9f17733af5e20500fbf858c","status":"affected","lessThan":"32ca4aed2a66205b072fcfecabe220289a8149ff","versionType":"git"},{"version":"8c6eabae3807e048b9f17733af5e20500fbf858c","status":"affected","lessThan":"2c6381d90898089287e0a358f06f89f6b4b389f2","versionType":"git"},{"version":"8c6eabae3807e048b9f17733af5e20500fbf858c","status":"affected","lessThan":"4d70986002f2f3eaaed89124fb2522bded38b016","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/iommu/iommufd/hw_pagetable.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.8","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.8","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/iommu/iommufd/hw_pagetable.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/d2bd041e0efaf7d81789779b135279d18b33d6d5"},{"url":"https://git.kernel.org/stable/c/32ca4aed2a66205b072fcfecabe220289a8149ff"},{"url":"https://git.kernel.org/stable/c/2c6381d90898089287e0a358f06f89f6b4b389f2"},{"url":"https://git.kernel.org/stable/c/4d70986002f2f3eaaed89124fb2522bded38b016"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T04:52:45.289Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"6.12.96"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"6.18.39"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"7.1.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.8","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}