CVE-2026-46243 | smb: client: reject userspace cifs.spnego descriptions

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.

Published: 2026-06-01 Last update: 2026-06-09 Assigner: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-46243 is rated Low Risk (29.9/100): CVSS High severity, with low exploitation likelihood (EPSS 0.14%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-46243

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.02% 0.14% +0.13%
2 2026-06-02 — 0.02% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-46243

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.1 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 1.8 5.2 416baaa9-dc9f-4396-8d5f-8c081fb06d67
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2026-46243

GitHub Security Advisory for CVE-2026-46243

GHSA-3mg7-pfmq-9qfv · Severity: high — In the Linux kernel, the following vulnerability has been resolved: smb: client: reject...

OS Trackers for CVE-2026-46243

vendor priority summary link
debian not yet assigned CVE-2026-46243 not yet assigned priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2026-46243
suse — — https://www.suse.com/security/cve/CVE-2026-46243/
ubuntu medium CVE-2026-46243 medium priority: Ubuntu including 158 source packages (linux, linux-allwinner-5.19, …), 1422 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): DNE 1024, ignored 173, needed 141, released 84. https://ubuntu.com/security/CVE-2026-46243

Affected software / configurations for CVE-2026-46243

Vendor Product Version Raw CPE
linux linux_kernel >= 2.6.24.1, < 5.10.258 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.11, < 5.15.209 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.16, < 6.1.175 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.2, < 6.6.142 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.7, < 6.12.92 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.13, < 6.18.34 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.19, < 7.0.11 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel 2.6.24 cpe:2.3:o:linux:linux_kernel:2.6.24:-:*:*:*:*:*:*
linux linux_kernel 2.6.24 cpe:2.3:o:linux:linux_kernel:2.6.24:rc3:*:*:*:*:*:*
linux linux_kernel 2.6.24 cpe:2.3:o:linux:linux_kernel:2.6.24:rc4:*:*:*:*:*:*
linux linux_kernel 2.6.24 cpe:2.3:o:linux:linux_kernel:2.6.24:rc5:*:*:*:*:*:*
linux linux_kernel 2.6.24 cpe:2.3:o:linux:linux_kernel:2.6.24:rc6:*:*:*:*:*:*
linux linux_kernel 2.6.24 cpe:2.3:o:linux:linux_kernel:2.6.24:rc7:*:*:*:*:*:*
linux linux_kernel 2.6.24 cpe:2.3:o:linux:linux_kernel:2.6.24:rc8:*:*:*:*:*:*
linux linux_kernel 7.1 cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*
linux linux_kernel 7.1 cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*
linux linux_kernel 7.1 cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*
linux linux_kernel 7.1 cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:*

References for CVE-2026-46243

cvelogic Threat Intelligence