CVE-2015-2929
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 · uneditedThe Hidden Service (HS) client implementation in Tor before 0.2.4.27, 0.2.5.x before 0.2.5.12, and 0.2.6.x before 0.2.6.7 allows remote servers to cause a denial of service (assertion failure and application exit) via a malformed HS descriptor.
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 confidenceThe Hidden Service client implementation in Tor contains a parsing vulnerability where a remote malicious hidden service server can send a malformed HS descriptor that triggers an assertion failure, causing the Tor client to exit unexpectedly.
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< 0.2.4.27>= 0.2.5.1, < 0.2.5.12>= 0.2.6.1, < 0.2.6.7CVSS 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
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 installed Tor versionRun `tor --version` or check your package manager for the installed tor package versionAffected if The version is less than 0.2.4.27, OR between 0.2.5.1 and 0.2.5.11 inclusive, OR between 0.2.6.1 and 0.2.6.6 inclusive
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Confirm Hidden Service client access is enabledVerify that Tor is configured to access hidden services; by default any Tor client can access .onion services - check your torrc configuration file for any ClientDNSPort, SOCKSPort, or hidden service directivesAffected if Tor client can access hidden services (this is the default behavior for standard Tor installations)
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Identify if running as a relay with hidden service functionalityCheck torrc for `HiddenServiceDir` and `HiddenServicePort` directives which configure hidden service hostingAffected if The system is configured as a hidden service (running a .onion service), as the vulnerability affects the client-side parsing of descriptors received from hidden service servers
You are affected if your Tor version falls within the vulnerable ranges AND your Tor client can access hidden services (default behavior), allowing a remote malicious hidden service to crash your client with a malformed descriptor.
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 data0.2.4.270.2.5.120.2.6.7
Upgrade Tor to version 0.2.4.27, 0.2.5.12, or 0.2.6.7 or later to obtain the patched version that properly handles malformed descriptors without crashing.
- Consultation1.0 h
- Implementation2.0 h
- Testing1.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2015-2929 — 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-2015-2929 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
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