net: page_pool: fix UAF in __page_pool_release_netmem_dma on xa_cmpxchg race

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-90201
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-17 17:17:15 UTC
Updated2026-09-17 17:17:15 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: net: page_pool: fix UAF in __page_pool_release_netmem_dma on xa_cmpxchg race This bug was discovered while testing the hns3 driver under channel reconfiguration (`ethtool -L` / `ethtool -G`) with iperf3 traffic on arm64. The race is intermittently triggered when page_pool_destroy() runs page_pool_scrub() concurrently with page return via page_pool_put_netmem() on a different CPU. A WARN in page_pool_clear_pp_info() surfaced the dangling DMA index bits left by the cmpxchg loser, which led to the investigation. page_pool_scrub() iterates pool->dma_mapped via xa_for_each() with no page ref held. __page_pool_release_netmem_dma() currently reads and writes netmem fields (dma_addr, DMA index bits in pp_magic) after xa_cmpxchg() returns. The unref path calls put_page() unconditionally regardless of the cmpxchg outcome; when it loses the cmpxchg, it still frees the page before the scrub winner finishes these netmem accesses, so scrub touches a freed page -- a Use-After-Free. Fix this by splitting the DMA release into two functions: 1. __page_pool_unmap_netmem_dma() caches dma_addr before xa_cmpxchg(), does the cmpxchg to remove the DMA mapping, and calls dma_unmap on the cached address. It never touches netmem fields after the cmpxchg, making it safe for the scrub path which holds no page ref. 2. __page_pool_release_netmem_dma() wraps the above and additionally clears dma_addr and DMA index bits in netmem fields. This is safe only when the caller holds a page ref, so it is used by the return path (page_pool_return_netmem). The scrub path calls __page_pool_unmap_netmem_dma() directly; the return path calls __page_pool_release_netmem_dma().

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 4f51fb0d257ff4d406ec27966902de075e3b118e bbfef303f980c1c078b8fa142e10a0e2fbcdd247 git Not specified
CNA Linux Linux affected ee62ce7a1d909ccba0399680a03c2dee83bcae95 424a9fc4876cc7f28e9cb0aa8d92e920d726e350 git Not specified
CNA Linux Linux affected ee62ce7a1d909ccba0399680a03c2dee83bcae95 9b65b0253ad5a66f73efee9a79a21a1e2b57cf59 git Not specified
CNA Linux Linux affected ee62ce7a1d909ccba0399680a03c2dee83bcae95 24ef02f934eeb48830cff6b739abc3c62b1d107b git Not specified
CNA Linux Linux affected c30ae60f41f9edd6e1b5cad41cf28ce04dae39e4 git Not specified
CNA Linux Linux affected 6.12.34 6.12.110 semver Not specified
CNA Linux Linux affected 6.15.3 6.16 semver Not specified
CNA Linux Linux affected 6.16 Not specified
CNA Linux Linux unaffected 6.16 semver Not specified
CNA Linux Linux unaffected 6.12.110 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.52 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.6 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/24ef02f934eeb48830cff6b739abc3c62b1d107b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/424a9fc4876cc7f28e9cb0aa8d92e920d726e350 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/9b65b0253ad5a66f73efee9a79a21a1e2b57cf59 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/bbfef303f980c1c078b8fa142e10a0e2fbcdd247 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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