CVE-2026-89985
CVE-2026-89985 is a security vulnerability. O3 Security confirms whether CVE-2026-89985 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
In the Linux kernel, the following vulnerability has been resolved: memcg: keep folio's objcg same as its node memcg_reparent_objcgs() has an inherent assumption that a folio's objcg…
Description
In the Linux kernel, the following vulnerability has been resolved:
memcg: keep folio's objcg same as its node
memcg_reparent_objcgs() has an inherent assumption that a folio's objcg is the objcg of the folio's node. Folio migration across nodes breaks that assumption: the new folio simply inherits the old folio's objcg while living on a different node.
Once the assumption is broken, the reparenting of the folio's objcg and the reparenting of the folio's LRU list are no longer atomic. memcg_reparent_objcgs() handles one node per iteration and drops all the locks in between, so the objcg gets reparented in the iteration for the objcg's node while the LRU list gets spliced in the iteration for the folio's node. Any LRU operation on that folio in between resolves its lruvec through the objcg, and thus takes the lru_lock of the wrong memcg, not the lru_lock of the list the folio is actually on.
Fix this by selecting the objcg by folio_nid() at charge time, and by re-deriving it for the destination node in mem_cgroup_migrate() and mem_cgroup_replace_folio().
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of the affected component has shipped for CVE-2026-89985 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-89985 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-89985. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-89985 in your dependencies?
O3 detects CVE-2026-89985 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.