CVE-2026-46243NVD status: Modified
In the Linux kernel, the following vulnerability has been resolved: smb: client: reject…
CVE-2026-46243 is a high-severity improper input validation 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 7713bd320ed4fc3d08a227cd8e41242219a16981, 9544559e59438a4b609b2fdfa0763d8360572824, cf20038657d6d4974349556a34e08fe0490bebbc 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 0.41% chance of exploitation within 30 days, which is low compared with other CVEs.
Next patch cycle
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 7713bd320ed4fc3d08a227cd8e41242219a16981 or 9544559e59438a4b609b2fdfa0763d8360572824 or cf20038657d6d4974349556a34e08fe0490bebbc or 2035acfb17221729b1b8ac335e941868a04ca079, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.258 or 5.15.209 or 6.1.175 or 6.6.142, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | f1d662a7d5e5322e583aad6b3cfec03d8f27b435 up to, but not including, 7713bd320ed4fc3d08a227cd8e41242219a16981; f1d662a7d5e5322e583aad6b3cfec03d8f27b435 up to, but not including, 9544559e59438a4b609b2fdfa0763d8360572824; f1d662a7d5e5322e583aad6b3cfec03d8f27b435 up to, but not including, cf20038657d6d4974349556a34e08fe0490bebbc; f1d662a7d5e5322e583aad6b3cfec03d8f27b435 up to, but not including, 2035acfb17221729b1b8ac335e941868a04ca079; f1d662a7d5e5322e583aad6b3cfec03d8f27b435 up to, but not including, a3bbda6502a9398b816fa2e71c9a3f955f58013d; f1d662a7d5e5322e583aad6b3cfec03d8f27b435 up to, but not including, 91f89c1d83e80417629791fcef6af8140d7d01c8; f1d662a7d5e5322e583aad6b3cfec03d8f27b435 up to, but not including, 0aece6685fc80a8de492688ca2315fb86ec379c7; f1d662a7d5e5322e583aad6b3cfec03d8f27b435 up to, but not including, 3da1fdf4efbc490041eb4f836bf596201203f8f2; and 1 more ranges | 7713bd320ed4fc3d08a227cd8e41242219a16981, 9544559e59438a4b609b2fdfa0763d8360572824, cf20038657d6d4974349556a34e08fe0490bebbc, 2035acfb17221729b1b8ac335e941868a04ca079, a3bbda6502a9398b816fa2e71c9a3f955f58013d, 91f89c1d83e80417629791fcef6af8140d7d01c8 |
| Red Hat | NVIDIA for RHEL 10 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 10 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 10.0 Extended Update Support | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSION | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 7 Extended Lifecycle Support | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8.8 Telecommunications Update Service | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9.6 Extended Update Support | Not specified in the record | Not stated |
| Red Hat | Red Hat OpenShift Container Platform 4.12 | Not specified in the record | Not stated |
| Red Hat | Red Hat OpenShift Container Platform 4.13 | Not specified in the record | Not stated |
| Red Hat | Red Hat OpenShift Container Platform 4.14 | Not specified in the record | Not stated |
| Red Hat | Red Hat OpenShift Container Platform 4.15 | Not specified in the record | Not stated |
| Red Hat | Red Hat OpenShift Container Platform 4.16 | Not specified in the record | Not stated |
| Red Hat | Red Hat OpenShift Container Platform 4.17 | Not specified in the record | Not stated |
| Red Hat | Red Hat OpenShift Container Platform 4.18 | Not specified in the record | Not stated |
| Red Hat | Red Hat OpenShift Container Platform 4.19 | Not specified in the record | Not stated |
Version data comes from the organisation that assigned the CVE; 4 further products are omitted here. 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
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N. Scored by CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.1 | High | CNA |
| CVSS 3.1 | 7.8 | High | CISA (ADP) |
| CVSS 3.1 | 7.8 | High | CNA |
Official description
In the Linux kernel, the following vulnerability has been resolved: smb: client: reject userspace cifs.spnego descriptions cifs.spnego key descriptions contain authority-bearing fields such as pid, uid, creduid, and upcall_target that cifs.upcall treats as kernel-originating inputs. However, userspace can also create keys of this type through request_key(2) or add_key(2), allowing those fields to be supplied without CIFS origin. Only accept cifs.spnego descriptions while CIFS is using its private spnego_cred to request the key.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
How developers prevent this class of flaw
- Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build recognizers for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of allowing parser code to be scattered throughout the program, where it could be subject to errors or inconsistencies that create weaknesses.
- Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
- Understand all the potential areas where untrusted inputs can enter the product, including but not limited to: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/0aece6685fc80a8de492688ca2315fb86ec379c7
- git.kernel.org/stable/c/2035acfb17221729b1b8ac335e941868a04ca079
- git.kernel.org/stable/c/3da1fdf4efbc490041eb4f836bf596201203f8f2
- git.kernel.org/stable/c/7713bd320ed4fc3d08a227cd8e41242219a16981
- git.kernel.org/stable/c/91f89c1d83e80417629791fcef6af8140d7d01c8
- git.kernel.org/stable/c/9544559e59438a4b609b2fdfa0763d8360572824
- git.kernel.org/stable/c/a3bbda6502a9398b816fa2e71c9a3f955f58013d
- git.kernel.org/stable/c/cf20038657d6d4974349556a34e08fe0490bebbc
Third-party and government advisories
- openwall.com/lists/oss-security/2026/06/01/6Mailing List, Third Party Advisory
- github.com/manizada/CIFSwitchThird Party Advisory
Other references
- access.redhat.com/errata/RHSA-2026:23258
- access.redhat.com/errata/RHSA-2026:23259
- access.redhat.com/errata/RHSA-2026:23329
- access.redhat.com/errata/RHSA-2026:23395
- access.redhat.com/errata/RHSA-2026:24381
- access.redhat.com/errata/RHSA-2026:25908
- access.redhat.com/errata/RHSA-2026:26462
- access.redhat.com/errata/RHSA-2026:26515
- access.redhat.com/errata/RHSA-2026:26535
- access.redhat.com/errata/RHSA-2026:26563
- access.redhat.com/errata/RHSA-2026:26570
- access.redhat.com/errata/RHSA-2026:27708
- access.redhat.com/errata/RHSA-2026:27719
- access.redhat.com/errata/RHSA-2026:27729
- access.redhat.com/errata/RHSA-2026:27735
Recent Improper Input Validation vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 9.1 Critical severity
- 8.8 High severity
- 8.1 High severity
- 9.1 Critical severity
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