CVE-2026-90103 — Kernel
HIGHCVE-2026-90103 is a high-severity (CVSS 7.5) vulnerability in Kernel. A fix is available for Kernel — see the affected versions and patch details below.
NFSv4.2: fix LAYOUTSTATS send buffer exhaustion
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.
How urgent is this, really
CVE-2026-90103 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
KernelReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Linux packages — download data is not available via public APIs for these ecosystems.
Description
In the Linux kernel, the following vulnerability has been resolved:
NFSv4.2: fix LAYOUTSTATS send buffer exhaustion
encode_layoutstats_maxsz budgets XDR_QUADLEN(PNFS_LAYOUTSTATS_MAXSIZE), i.e. 256 bytes, for the layoutupdate4 body written by the layout driver. The flexfiles record can exceed that.
ff_layout_encode_ff_layoutupdate() emits, per data server, a netaddr4, an nfs_fh4, two ff_io_latency4, an nfstime4 and a bool. A data server whose filehandle is NFS_MAXFHSIZE bytes long already accounts for 132 of those bytes, and the two ff_io_latency4 at 64 bytes each, the nfstime4 and the bool add a further 144, so the body passes 256 bytes before the netaddr4 is encoded at all. encode_layoutstats() additionally writes the deviceid4 and the layoutupdate4 lou_type word, neither of which the macro accounts for.
The filehandle and the address are both chosen by the server, through LAYOUTGET and GETDEVICEINFO, so it can drive the encoder past the end of the send buffer. xdr_reserve_space() returns NULL once that happens, and the two ff_layout_encode_io_latency() calls run with dss_info->mirror->lock held, so a NULL return there leaves the lock permanently held.
Raise PNFS_LAYOUTSTATS_MAXSIZE to 384 so that the record fits inside the reservation.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐧Linux | Kernel | ≥ 4.2.0&&< 5.10.270 | 5.10.270 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Kernel, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update Kernel to 5.10.270 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-90103 is resolved across your whole dependency graph.
Workarounds
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-2026-90103 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-90103. 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-2026-90103 in your dependencies?
O3 Security finds CVE-2026-90103 across Linux dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.