CVE-2025-30347
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 · uneditedVarnish Enterprise before 6.0.13r13 allows remote attackers to obtain sensitive information via an out-of-bounds read for range requests on ephemeral MSE4 stevedore objects.
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 · moderate confidenceVarnish Enterprise before version 6.0.13r13 contains an out-of-bounds read vulnerability in the MSE4 stevedore storage engine. Remote attackers can exploit HTTP range requests on ephemeral MSE4 objects to read memory beyond intended boundaries, potentially exposing sensitive data.
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= 6.0.13CVSS 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
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
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 installed Varnish Enterprise versionRun 'varnishd -V' or 'varnishadm param.show version' to determine the exact version of Varnish Enterprise installed.Affected if The version is exactly 6.0.13 (the only version listed as affected). Versions before 6.0.13 are not affected by this specific CVE, and later versions (6.0.13r3 and above) contain the patch.
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Verify MSE4 stevedore is in useCheck Varnish configuration files (varnish.ini, default.vcl) for 'storage = "mse4"' or similar MSE4 storage backend declarations, or run 'varnishadm param.show storage' to list active storage engines.Affected if MSE4 stevedore storage engine is configured and actively used. Without MSE4 storage, this vulnerability does not apply.
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Confirm ephemeral MSE4 objects are in useReview MSE4 configuration for ephemeral object settings (typically 'mse_efi' or similar ephemeral file indicators in the storage configuration), or inspect runtime storage status via varnishadm.Affected if Ephemeral MSE4 objects are created and managed by the storage engine. The vulnerability specifically affects ephemeral MSE4 objects, not persistent ones.
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Check if HTTP range requests are processedExamine Varnish configuration for 'http_range' handling or look for range request-related backend responses in logs. Range requests are standard HTTP requests with a 'Range' header.Affected if HTTP range requests can be made against objects stored in ephemeral MSE4 storage. The vulnerability is triggered specifically by range request handling on these objects.
A system is affected only if it runs Varnish Enterprise version 6.0.13 with MSE4 stevedore storage configured for ephemeral objects that accept HTTP range requests.
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.
dbcve · scopedUpgrade Varnish Enterprise to version 6.0.13r3 or later to patch the vulnerability. If immediate patching is not possible, consider restricting or disabling range request functionality on ephemeral MSE4 storage as a temporary workaround.
Varnish Enterprise 6.0.13r13 or later
- Upgrade Varnish Enterprise to version 6.0.13r13 or later to address the out-of-bounds read vulnerability in MSE4 stevedore range requests
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA3.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-30347 — 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-2025-30347 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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- 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
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