CVE-2026-89961 — Linux kernel
CVE-2026-89961 is a security vulnerability. No vendor fix is recorded yet; mitigation options are listed below.
In the Linux kernel, the following vulnerability has been resolved: powerpc/mm: fix wrong addr_pfn tracking in compound vmemmap population vmemmap_populate_compound_pages() uses addr_pfn…
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Description
In the Linux kernel, the following vulnerability has been resolved:
powerpc/mm: fix wrong addr_pfn tracking in compound vmemmap population
vmemmap_populate_compound_pages() uses addr_pfn to determine the PFN offset within a compound page and to decide whether the current vmemmap slot should be populated as a head page mapping or should reuse a tail page mapping.
However, addr_pfn is advanced manually in parallel with addr. The loop itself progresses in vmemmap address space, so each PAGE_SIZE step in addr covers PAGE_SIZE / sizeof(struct page) struct page slots. Since addr_pfn is compared against nr_pages in data-PFN units, it should advance by the same number of PFNs. The existing manual increments do not match that and therefore do not reliably track the PFN corresponding to the current addr.
As a result, pfn_offset can be computed from the wrong PFN and the code can make the head/tail decision for the wrong compound-page position.
Fix this by deriving addr_pfn directly from the current vmemmap address instead of carrying it as loop state.
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of the affected component has shipped for CVE-2026-89961 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-89961 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-89961. 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-2026-89961 in your dependencies?
O3 Security finds CVE-2026-89961 across dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.