CVE-2026-46243: smb: client: reject userspace cifs.spnego descriptions
Vulnerability summary
CVE-2026-46243 is a high (CVSS 7.1) Improper Input Validation vulnerability in linux. EPSS estimates a 0.41% chance of exploitation in the next 30 days, higher than 35.6% of scored vulnerabilities. 1 public exploit is recorded.
Public exploit (GitHub, Date unknown)
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 226 · Related 211Showing 100 of 232.
Timeline
- 01-06-2026PublishedVulnerability first disclosed.
- 15-10-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
6 scores · 5 sources · 2 versions- OSV · Red hatEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HDiffers
- OSV · UbuntuEcosystem advisory · calculated7.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
- OSV · DebianEcosystem advisory · calculated7.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
- NVDNIST7.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
EPSS trend
Probability
0.41%
Chance of exploitation in the next 30 days
Percentile
36%
Versus all other CVEs
30-day change
Increase +0.21 pp
From 0.20% on 04-10-2026
Known exploited
Compare KEV catalogsNot in the CISA KEV catalog.
Not in the ENISA CNW catalog.
Not in the CIRCL catalog.
Public exploits
1 foundCifswitch
Maturity: poc
Weaknesses
CWE · root cause- CWE-20Improper Input ValidationThe 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.
- CWE-825Expired Pointer DereferenceThe product dereferences a pointer that contains a location for memory that was previously valid, but is no longer valid.
Affected systems
Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu163 products
- linux< 3.13.0-214.265 | < 4.4.0-283.317 | < 4.15.0-253.265 | < 5.4.0-233.253 | < 5.15.0-185.195 | < 6.8.0-134.134 | < 6.17.0-40.40 | < 7.0.0-27.27
- linux-allwinner-5.19All versions (No fix recorded)
- linux-aws< 4.4.0-1156.162 | < 4.4.0-1194.209 | < 4.15.0-1194.207 | < 5.4.0-1161.172 | < 5.15.0-1111.118 | < 6.8.0-1060.63 | < 6.17.0-1019.19 | < 7.0.0-1008.8
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Redhat34 products
- bpftool< 0:4.18.0-553.129.1.el8_10
- bpftool-debuginfo< 0:4.18.0-553.129.1.el8_10
- kernel< 0:4.18.0-553.129.1.el8_10 | < 0:6.12.0-212.9.el10nv
- kernel-64k< 0:6.12.0-212.9.el10nv
- kernel-64k-core< 0:6.12.0-212.9.el10nv
Linux2 products
- linux≥ f1d662a7d5e5322e583aad6b3cfec03d8f27b435, < 7713bd320ed4fc3d08a227cd8e41242219a16981 | ≥ f1d662a7d5e5322e583aad6b3cfec03d8f27b435, < 9544559e59438a4b609b2fdfa0763d8360572824 | ≥ f1d662a7d5e5322e583aad6b3cfec03d8f27b435, < cf20038657d6d4974349556a34e08fe0490bebbc | ≥ f1d662a7d5e5322e583aad6b3cfec03d8f27b435, < 2035acfb17221729b1b8ac335e941868a04ca079 | ≥ f1d662a7d5e5322e583aad6b3cfec03d8f27b435, < a3bbda6502a9398b816fa2e71c9a3f955f58013d | ≥ f1d662a7d5e5322e583aad6b3cfec03d8f27b435, < 91f89c1d83e80417629791fcef6af8140d7d01c8 | ≥ f1d662a7d5e5322e583aad6b3cfec03d8f27b435, < 0aece6685fc80a8de492688ca2315fb86ec379c7 | ≥ f1d662a7d5e5322e583aad6b3cfec03d8f27b435, < 3da1fdf4efbc490041eb4f836bf596201203f8f2 | 2.6.24
- linux_kernel≥ 2.6.24.1, < 5.10.258 | ≥ 5.11, < 5.15.209 | ≥ 5.16, < 6.1.175 | ≥ 6.2, < 6.6.142 | ≥ 6.7, < 6.12.92 | ≥ 6.13, < 6.18.34 | ≥ 6.19, < 7.0.11 | 2.6.24 | 2.6.24:rc3 | 2.6.24:rc4 | 2.6.24:rc5 | 2.6.24:rc6 | 2.6.24:rc7 | 2.6.24:rc8 | 7.1:rc1 | 7.1:rc2 | 7.1:rc3 | 7.1:rc4
Debian1 product
- linux< 6.1.174-1 | < 6.12.90-2 | < 7.0.10-1
4 vendors · 200 products · Showing 200 of 237
References
107 linksShow all 100 references
- git.kernel.org/pub/…ARTICLE
Showing 100 of 107.