{"cve":"CVE-2026-90201","nvd":{"published":"2026-09-17T17:17:15.053","modified":"2026-10-19T09:19:10.163","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: page_pool: fix UAF in __page_pool_release_netmem_dma on xa_cmpxchg race\n\nThis bug was discovered while testing the hns3 driver under channel\nreconfiguration (`ethtool -L` / `ethtool -G`) with iperf3 traffic on\narm64. The race is intermittently triggered when page_pool_destroy()\nruns page_pool_scrub() concurrently with page return via\npage_pool_put_netmem() on a different CPU. A WARN in\npage_pool_clear_pp_info() surfaced the dangling DMA index bits left\nby the cmpxchg loser, which led to the investigation.\n\npage_pool_scrub() iterates pool->dma_mapped via xa_for_each() with no\npage ref held. __page_pool_release_netmem_dma() currently reads and\nwrites netmem fields (dma_addr, DMA index bits in pp_magic) after\nxa_cmpxchg() returns. The unref path calls put_page() unconditionally\nregardless of the cmpxchg outcome; when it loses the cmpxchg, it still\nfrees the page before the scrub winner finishes these netmem accesses,\nso scrub touches a freed page -- a Use-After-Free.\n\nFix this by splitting the DMA release into two functions:\n\n1. __page_pool_unmap_netmem_dma() caches dma_addr before xa_cmpxchg(),\n   does the cmpxchg to remove the DMA mapping, and calls dma_unmap on\n   the cached address. It never touches netmem fields after the cmpxchg,\n   making it safe for the scrub path which holds no page ref.\n\n2. __page_pool_release_netmem_dma() wraps the above and additionally\n   clears dma_addr and DMA index bits in netmem fields. This is safe\n   only when the caller holds a page ref, so it is used by the return\n   path (page_pool_return_netmem).\n\nThe scrub path calls __page_pool_unmap_netmem_dma() directly; the return\npath calls __page_pool_release_netmem_dma().","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/24ef02f934eeb48830cff6b739abc3c62b1d107b","https://git.kernel.org/stable/c/424a9fc4876cc7f28e9cb0aa8d92e920d726e350","https://git.kernel.org/stable/c/9b65b0253ad5a66f73efee9a79a21a1e2b57cf59","https://git.kernel.org/stable/c/bbfef303f980c1c078b8fa142e10a0e2fbcdd247"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:55:23.253742848+00:00"},"epss":{"cve":"CVE-2026-90201","score":0.00206,"percentile":0.1045,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}