CVE-2026-90201 — net: page_pool: fix UAF in __page_pool_release_netmem_dma on xa_cmpxchg race
In 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().
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.2% (30-day exploitation probability)+1
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes, errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Linux | Linux | ≥ 4f51fb0d257ff4d406ec27966902de075e3b118e and < bbfef303f980c1c078b8fa142e10a0e2fbcdd247≥ ee62ce7a1d909ccba0399680a03c2dee83bcae95 and < 424a9fc4876cc7f28e9cb0aa8d92e920d726e350≥ ee62ce7a1d909ccba0399680a03c2dee83bcae95 and < 9b65b0253ad5a66f73efee9a79a21a1e2b57cf59≥ ee62ce7a1d909ccba0399680a03c2dee83bcae95 and < 24ef02f934eeb48830cff6b739abc3c62b1d107bversion c30ae60f41f9edd6e1b5cad41cf28ce04dae39e4≥ 6.12.34 and < 6.12.110≥ 6.15.3 and < 6.16version 6.16 | Vulnerable | CVE Program (cve.org) e CISA ADP |
EPSS over time FIRST
Oct 15, 2026 → Oct 18, 2026 · 3 reading(s) · max 0.21%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Not enough vector or weakness data: use the affected application’s logs as a starting point.
Timeline
What happened to this CVE, newest first.
- 2026
- Record published
- Affected products added · linux/linux
- Source status changed · → Received
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× References added · Oct 19, 2026 – Oct 19, 2026
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
6 on the record
- git.kernel.org/stable/c/424a9fc4876cc7f28e9cb0aa8d92e920d726e350
- git.kernel.org/stable/c/bbfef303f980c1c078b8fa142e10a0e2fbcdd247
- git.kernel.org/stable/c/24ef02f934eeb48830cff6b739abc3c62b1d107b
- nvd.nist.gov/vuln/detail/CVE-2026-90201
- github.com/advisories/GHSA-6rvq-r5r4-hcv8
- git.kernel.org/stable/c/9b65b0253ad5a66f73efee9a79a21a1e2b57cf59
Elsewhere on this site
Related CVEs (same products)
- Unknown CVE-2026-98868 dm-pcache: reject a kset that overruns its segment 1d
- Unknown CVE-2026-98867 dm-pcache: bound the logical key offset from persistent memory 1d
- Unknown CVE-2026-98866 sched/cache: Introduce task_struct->sched_cache_grp to fix UAF 1d
- Unknown CVE-2026-98858 io_uring: fix task_work add use-after-free with SQPOLL 1d
- Unknown CVE-2026-98865 sched_ext: Don't run ops.dequeue() with a DSQ lock held 1d
- Unknown CVE-2026-98864 sched_ext: Wait for SCX_OPSS_DISPATCHING before reenqueueing a task 1d
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No CVSS score published by NVD, the CNA, CISA or GitHub so far.
- No fixed version, patch or mitigation documented.
- No CISA SSVC assessment.
- No CWE classification.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-90201 is "net: page_pool: fix UAF in __page_pool_release_netmem_dma on xa_cmpxchg race", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. EPSS 0.21% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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