Linux: Out-of-bounds Read
CVE-2026-31568 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 48eda93e50f8361dee8e261fe55d0b31714e1e56, 1eb35c54cd81cf874ce7d69e3dbfb162f211b8bd, b36b0e804aee5f20c6798dbeaeaa7cfdb7c6cf88 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.16% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 48eda93e50f8361dee8e261fe55d0b31714e1e56 or 1eb35c54cd81cf874ce7d69e3dbfb162f211b8bd or b36b0e804aee5f20c6798dbeaeaa7cfdb7c6cf88 or 43ac2d18db1131df0a89993f709131ebfc29f3bd, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.18.21 or 6.19.11, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 084ea4d611a3d00ee3930400b262240e10895900 up to, but not including, 48eda93e50f8361dee8e261fe55d0b31714e1e56; 084ea4d611a3d00ee3930400b262240e10895900 up to, but not including, 1eb35c54cd81cf874ce7d69e3dbfb162f211b8bd; 084ea4d611a3d00ee3930400b262240e10895900 up to, but not including, b36b0e804aee5f20c6798dbeaeaa7cfdb7c6cf88; 084ea4d611a3d00ee3930400b262240e10895900 up to, but not including, 43ac2d18db1131df0a89993f709131ebfc29f3bd; 084ea4d611a3d00ee3930400b262240e10895900 up to, but not including, b00be77302d7ec4ad0367bb236494fce7172b730; 5.7 | 48eda93e50f8361dee8e261fe55d0b31714e1e56, 1eb35c54cd81cf874ce7d69e3dbfb162f211b8bd, b36b0e804aee5f20c6798dbeaeaa7cfdb7c6cf88, 43ac2d18db1131df0a89993f709131ebfc29f3bd, b00be77302d7ec4ad0367bb236494fce7172b730 |
| Linux | Linux Kernel | 5.7.1 up to, but not including, 6.18.21; 6.19 up to, but not including, 6.19.11; 5.7; 7.0 | 6.18.21, 6.19.11 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H. Scored by NVD.
Official description
In the Linux kernel, the following vulnerability has been resolved: s390/mm: Add missing secure storage access fixups for donated memory There are special cases where secure storage access exceptions happen in a kernel context for pages that don't have the PG_arch_1 bit set. That bit is set for non-exported guest secure storage (memory) but is absent on storage donated to the Ultravisor since the kernel isn't allowed to export donated pages. Prior to this patch we would try to export the page by calling arch_make_folio_accessible() which would instantly return since the arch bit is absent signifying that the page was already exported and no further action is necessary. This leads to secure storage access exception loops which can never be resolved. With this patch we unconditionally try to export and if that fails we fixup.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Out-of-bounds Read
The product reads data past the end, or before the beginning, of the intended buffer.
How developers prevent this class of flaw
- Use a language that provides appropriate memory abstractions.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
Recent Out-of-bounds Read vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 9.1 Critical severity
- 9.1 Critical severity
- 9.1 Critical severity
- 7.8 High severity
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