CVE-2026-46289: Linux Kernel vulnerability (CVSS 9.8)

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.

CVSS 3.1 breakdown

Attack vectorNetwork

Attack complexityLow

Privileges requiredNone

User interactionNone

ScopeUnchanged

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Linux Kernel≥ 6.13 < 6.18.30 · ≥ 6.19 < 7.0.7 · ≥ 6.3 < 6.6.140 · ≥ 6.7 < 6.12.88

Remediation

Fixed in

Linux Kernel≥ 6.18.30

Patch & vendor advisories

References

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

Frequently asked

Is CVE-2026-46289 being actively exploited?

CVE-2026-46289 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.67%.

How severe is CVE-2026-46289?

CVE-2026-46289 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 0.67% probability of exploitation.

Which products are affected by CVE-2026-46289?

Affected products include Linux Kernel.

How do I fix CVE-2026-46289?

Upgrade affected software to a fixed version, for example Linux Kernel 6.18.30 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

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