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FreeBSDOperating system

CVE-2026-45250

HIGH · 7.8 CVSS v3.1 Published 2026-05-21
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
80/100
Remediation priority · High
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
The setcred(2) system call is only available to privileged users. However, before the privilege level of the caller is checked, the user-supplied list of supplementary groups is copied into a fixed-size kernel stack buffer without first validating its length. If the supplied list exceeds the capacity of that buffer, a stack buffer overflow occurs. Because the bounds check on the supplementary groups list occurs after the kernel stack buffer has already been written, an unprivileged local user may trigger the overflow without holding any special privilege. Successful exploitation may allow an attacker to execute arbitrary code in the context of the kernel, allowing an unprivileged local user to gain elevated privileges on the affected system.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A stack buffer overflow vulnerability exists in the setcred(2) system call where user-supplied supplementary groups are copied into a fixed-size kernel stack buffer without validating the input length first. The bounds check occurs after the copy operation, allowing an unprivileged local user to overflow the buffer and execute arbitrary code in kernel context, achieving privilege escalation.

MitigationApply kernel patches from the vendor to fix the setcred(2) bounds checking issue; consider restricting access to setcred(2) or disabling the supplementary groups feature until the patch can be deployed.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
FreeBSDOperating system
Affected:= 14.3= 14.4= 15.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check FreeBSD version
    Run `uname -r` or `freebsd-version` to identify the installed FreeBSD release version
    Affected if The version is 14.3, 14.4, or 15.0 exactly as shown in the affected versions list
  2. Verify unprivileged local users exist
    Check for non-root users on the system using `cat /etc/passwd` or `getent passwd` to list user accounts
    Affected if The system has one or more unprivileged user accounts that could invoke the setcred(2) system call
  3. Confirm setcred(2) syscall accessibility
    The setcred(2) syscall is a kernel interface and is accessible by default to all local users; no special configuration or module needs to be enabled for the vulnerability to apply
    Affected if The syscall is available to unprivileged users, which is the default state on affected FreeBSD versions
  4. Check for suspicious process activity
    Monitor for processes making unusual setcred(2) calls using system audit logs or `procstat -s` if available, or review /var/log/messages for any related errors
    Affected if Unusual or excessive setcred(2) syscall activity is observed from user processes

A user is affected if they are running FreeBSD version 14.3, 14.4, or 15.0 and the system permits unprivileged local user access, since the vulnerability is triggered via the setcred(2) syscall by any local user.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply kernel patches from the vendor to fix the setcred(2) bounds checking issue; consider restricting access to setcred(2) or disabling the supplementary groups feature until the patch can be deployed.

Recommended fix Moderate confidence

FreeBSD 14.4 or later stable release (contact security.freebsd.org for exact advisory FSA-xxx)

  1. Check current FreeBSD version using: uname -r
  2. Update the FreeBSD ports tree to the latest available: portsnap fetch update
  3. Upgrade FreeBSD to the latest stable release using: freebsd-update fetch install or rebuild from sources
  4. Reboot the system to load the patched kernel
  5. Verify the fix by checking the kernel version matches the patched release
Caveat Kernel upgrade requires system downtime and may require rebuilding third-party kernel modules

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in FreeBSD Scoped from the published advisory
  • Consultation8.0 h
  • Implementation24.0 h
  • Testing16.0 h
  • Review / QA8.0 h
56.0 hours of engineering $9,760
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-45250 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data