CVE-2026-64031 — Kernel
HIGHCVE-2026-64031 is a high-severity (CVSS 7.8) CWE-362 vulnerability in Kernel. A fix is available for Kernel — see the affected versions and patch details below.
erofs: fix managed cache race for unaligned extents
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
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:
erofs: fix managed cache race for unaligned extents
After unaligned compressed extents were introduced, the following race could occur:
[Thread 1] [Thread 2] (z_erofs_fill_bio_vec) <handle a Z_EROFS_PREALLOCATED_FOLIO folio> ... filemap_add_folio (1) (z_erofs_bind_cache) <the same folio is found..> .. .. folio_attach_private (2) filemap_add_folio (3) again
Since (1) is executed but (2) hasn't been executed yet, it's possible that another thread finds the same managed folio in z_erofs_bind_cache() for a different pcluster and calls filemap_add_folio() again since folio->private is still Z_EROFS_PREALLOCATED_FOLIO.
Fix this by explicitly clearing folio->private before making the folio visible in the managed cache so that another pcluster can simply wait on the locked managed folio as what we did for other shared cases [1].
This only impacts unaligned data compression (-E48bit with zstd,
for example).
[1] Commit 9e2f9d34dd12 ("erofs: handle overlapped pclusters out of crafted images properly") was originally introduced to handle crafted overlapped extents, but it addresses unaligned extents as well.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐧Linux | Kernel | ≥ 6.15.0&&< 6.18.34 | 6.18.34 |
Affected Products
linux kernellinuxDetection & 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 6.18.34 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-64031 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.
Frequently Asked Questions
Is CVE-2026-64031 in your dependencies?
Find it across Linux, including transitive dependencies.