CVE-2026-46289
CRITICALIn the Linux kernel, the following vulnerability has been resolved: lib/scatterlist: fix length calculations in extract_kvec_to_sg Patch series "Fix bugs in extract_iter_to_sg()",…
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:
lib/scatterlist: fix length calculations in extract_kvec_to_sg
Patch series "Fix bugs in extract_iter_to_sg()", v3.
Fix bugs in the kvec and user variants of extract_iter_to_sg. This series is growing due to useful remarks made by sashiko.dev.
The main bugs are:
- The length for an sglist entry when extracting from a kvec can exceed the number of bytes in the page. This is obviously not intended.
- When extracting a user buffer the sglist is temporarily used as a scratch buffer for extracted page pointers. If the sglist already contains some elements this scratch buffer could overlap with existing entries in the sglist.
The series adds test cases to the kunit_iov_iter test that demonstrate all of these bugs. Additionally, there is a memory leak fix for the test itself.
The bugs were orignally introduced into kernel v6.3 where the function lived in fs/netfs/iterator.c. It was later moved to lib/scatterlist.c in v6.5. Thus the actual fix is only marked for backports to v6.5+.
This patch (of 5):
When extracting from a kvec to a scatterlist, do not cross page boundaries. The required length was already calculated but not used as intended.
Adjust the copied length if the loop runs out of sglist entries without extracting everything.
While there, return immediately from extract_iter_to_sg if there are no sglist entries at all.
A subsequent commit will add kunit test cases that demonstrate that the patch is necessary.
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-2026-46289 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-2026-46289 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-2026-46289. 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-2026-46289 in your dependencies?
O3 detects CVE-2026-46289 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.