GoApplication · Golang
CVE-2016-3959
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 Verify function in crypto/dsa/dsa.go in Go before 1.5.4 and 1.6.x before 1.6.1 does not properly check parameters passed to the big integer library, which might allow remote attackers to cause a denial of service (infinite loop) via a crafted public key to a program that uses HTTPS client certificates or SSH server libraries.
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 DSAVerify function in Go's crypto/dsa package fails to properly validate parameters before passing them to the big integer library, allowing a maliciously crafted DSA public key to trigger an infinite loop, causing denial of service in applications using HTTPS client certificates or SSH server libraries.
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
GoApplication
= 1.6<= 1.5
FedoraOperating system
= 22= 23= 24= 42.1CVSS 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:3.0/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.
-
Determine the installed Go versionRun 'go version' or check /usr/local/go/VERSION for the Go toolchain, or inspect the binary with 'binaryname --version' if it's a distributed applicationAffected if The version shown is 1.6.0 or any 1.5.x release (1.5 through 1.5.x)
-
Identify applications using crypto/dsaSearch application source code for 'import crypto/dsa' or review compiled binary imports using tools like 'go tool nm' or 'objdump'Affected if The application imports and uses the crypto/dsa package for DSA verification
-
Check if HTTPS client certificate validation is in useReview application configuration and code for TLS client authentication (client certificates), which relies on crypto/dsa for certificate validationAffected if The application validates DSA-based client certificates in TLS connections
-
Check if SSH server functionality is in useReview application for SSH server implementation (look for ssh.ListenAndServe or similar SSH library usage)Affected if The application runs an SSH server using DSA keys for authentication
-
Verify the operating system versionRun 'cat /etc/os-release' (Fedora) or 'cat /etc/SuSE-release' (openSUSE) to determine the OS versionAffected if Running Fedora 22, 23, or 24, or openSUSE Leap 42.1, which ship with vulnerable Go versions
You are affected if your Go version is 1.6.0 or any 1.5.x release AND your application uses crypto/dsa for certificate validation or SSH operations.
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 dataUpgrade Go to version 1.6.1 or later (or 1.5.4+ for the 1.5.x branch) and recompile all affected binaries that use crypto/dsa for certificate validation or SSH operations.
Fix this in Go
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing4.0 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 $3,328.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-3959 — 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-2016-3959 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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.
- 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