dbcve.org
FreeBSDOperating system

CVE-2026-35547

HIGH · 8.1 CVSS v3.1 Published 2026-04-30
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
90/100
Remediation priority · Urgent
Remotely reachable No privileges 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
When processing the header of an incoming message, libnv failed to properly validate the message size. The lack of validation allows a malicious program to write outside the bounds of a heap allocation. This can trigger a crash or system panic, and it may be possible for an unprivileged user to exploit the bug to elevate their privileges.

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

libnv library lacks proper validation of message size fields in incoming message headers before allocating heap memory and copying data. This allows an attacker to trigger a heap buffer overflow by providing a crafted message with a size value larger than the allocated buffer, potentially leading to arbitrary code execution or privilege escalation.

MitigationImplement rigorous bounds checking on all message size fields before heap allocation. Validate that the claimed message size does not exceed the maximum expected size and matches the actual buffer allocation.

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:= 13.5= 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
Network
Complexity
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:H/PR:N/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. Identify the FreeBSD version
    Run 'uname -a' or 'freebsd-version -u' to determine the installed FreeBSD version
    Affected if The version matches 13.5, 14.3, 14.4, or 15.0 exactly
  2. Locate libnv library on the system
    Run 'find / -name "libnv*" -type f 2>/dev/null' to find libnv library files
    Affected if The libnv library is present on the system
  3. Identify services or applications using libnv
    Run 'ldd /bin/* /usr/bin/* 2>/dev/null | grep libnv' or check running processes that may link against libnv
    Affected if Any executable is linked against libnv and handles incoming network or inter-process messages
  4. Check for exposed network services using libnv
    Review running network services with 'sockstat -4l' or 'sockstat -6l' and correlate with libnv-using applications
    Affected if A service that uses libnv is bound to a network interface and may receive untrusted messages
  5. Inspect message handling configurations
    Examine configuration files for services using libnv to determine if they accept external input
    Affected if The libnv-using service is configured to accept remote or untrusted client connections

You are affected if you are running FreeBSD 13.5, 14.3, 14.4, or 15.0 and have any service or application linked against libnv that handles external or untrusted message input.

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

Implement rigorous bounds checking on all message size fields before heap allocation. Validate that the claimed message size does not exceed the maximum expected size and matches the actual buffer allocation.

Recommended fix Moderate confidence

FreeBSD 15.1 or latest stable branch

  1. Check current FreeBSD version with: uname -a
  2. Plan a maintenance window for the upgrade
  3. Backup all critical data and configuration files
  4. For production systems, test the upgrade in a non-production environment first
  5. Upgrade FreeBSD to the latest stable release (15.1 or newer) using freebsd-update or source rebuild
  6. Reboot the system into the new kernel
  7. Verify the libnv library has been updated and the vulnerability is resolved
  8. Verify all services start correctly after reboot
Caveat Standard FreeBSD upgrade risks apply - review Release Notes for any configuration or compatibility changes before upgrading production systems

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

Fix this in FreeBSD Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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Scan for this in your stack

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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-2026-35547 in production — separate from our analysis above.

No notes yet

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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