FreeBSDOperating system
CVE-2026-45258
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 · unediteddsp_mmap_single() validated the requested mapping by checking the sum of the user-supplied offset and length against the buffer size. This addition could overflow, so that a large offset and length wrapped around and passed the check. The offset was then narrowed from 64 to 32 bits when converted to a buffer address, yielding a mapping that extended past the audio buffer into unrelated kernel memory. The /dev/dsp device nodes are world-accessible by default. On a system with an audio device, either issue allows an unprivileged local user to read and write kernel memory, which can be used to escalate privileges, potentially gaining full control of the affected system. At a minimum, an attacker can crash the kernel, resulting in a Denial of Service (DoS).
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 confidenceInteger overflow in dsp_mmap_single() allows unprivileged local users to map kernel memory via /dev/dsp. The bounds check (offset + length vs buffer size) overflows, and 64-to-32-bit narrowing then maps beyond the audio buffer into adjacent kernel memory, enabling read/write access to kernel space.
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
= 14.3= 14.4= 15.0CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Check FreeBSD versionRun 'uname -r' or check /usr/include/osreldate.h to identify the installed FreeBSD versionAffected if Version is 14.3, 14.4, or 15.0 and matches the affected ranges exactly
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Verify /dev/dsp device existsRun 'ls -la /dev/dsp' to confirm the OSS audio device node is present in the systemAffected if The device node /dev/dsp exists on the system
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Inspect /dev/dsp permissionsRun 'ls -la /dev/dsp' and check the file permissions (mode bits) and ownershipAffected if The device is readable/writable by non-root users (e.g., mode includes 'o+rw', 'g+rw' for user's group, or is world-writable)
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Test unprivileged access to /dev/dspAs a non-root user, attempt 'dd if=/dev/dsp of=/dev/null bs=1 count=1' or check groups with 'groups' command and verify if the user belongs to a group granted access to /dev/dspAffected if An unprivileged user can successfully open /dev/dsp for reading or writing
You are affected if running FreeBSD 14.3, 14.4, or 15.0 AND unprivileged users can access /dev/dsp due to permissive device permissions.
Generated from the published advisory. Verify against your own configuration.
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.
From vendor dataRestrict /dev/dsp device node permissions (e.g., chmod 600 or set ownership to root:audio) to prevent unprivileged access. For permanent fix, apply kernel patch addressing the integer overflow in the OSS audio driver.
Fix this in FreeBSD
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-45258 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-45258 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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