FedoraOperating system · Fedoraproject
CVE-2016-2850
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 · uneditedBotan 1.11.x before 1.11.29 does not enforce TLS policy for (1) signature algorithms and (2) ECC curves, which allows remote attackers to conduct downgrade attacks via unspecified vectors.
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 confidenceBotan 1.11.x TLS implementation fails to enforce the configured policy for signature algorithms and ECC curves during TLS handshakes, allowing remote attackers to force downgrade to weaker cryptographic parameters by manipulating the cipher suite negotiation.
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
FedoraOperating system
= 24= 1.11.0= 1.11.1= 1.11.2= 1.11.3= 1.11.4= 1.11.5= 1.11.6= 1.11.7= 1.11.8= 1.11.9= 1.11.10= 1.11.11CVSS 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
- High
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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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Identify if Botan TLS library is in useSearch for installed Botan library files, check application dependencies, or examine loaded libraries in running TLS processes. Look for package names containing 'botan' or library files like libbotan.*Affected if Botan TLS library is present and used by any application or service in the environment
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Determine the installed Botan versionQuery the installed package manager for botan version (e.g., 'rpm -qa | grep botan' on Fedora, or check library version string). Compare the version number against the affected range 1.11.0 through 1.11.11Affected if The installed Botan version falls within 1.11.0 to 1.11.11 inclusive
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Verify TLS policy configuration existsInspect TLS configuration files, application TLS settings, or code that initializes the Botan TLS policy. Look for any configured constraints on allowed signature algorithms (such as RSA, DSA, ECDSA) or ECC curvesAffected if A TLS policy specifying restrictions on signature algorithms or ECC curves is configured, but the implementation does not enforce it during handshake negotiation
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Confirm TLS handshake functionality is activeCheck for running TLS-enabled services or applications that utilize the Botan library. Monitor network listeners on ports commonly used for TLS (443, 8443, etc.) or examine active connectionsAffected if TLS connections can be established using the Botan library, allowing an attacker to manipulate cipher suite negotiation
The environment is affected if it runs any application using Botan TLS version 1.11.0 through 1.11.11 with a configured policy that the implementation fails to enforce during handshake negotiation.
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 Botan to version 1.11.29 or later which enforces TLS policy for signature algorithms and ECC curves, and verify that TLS configuration rejects legacy/weak algorithms.
Fix this in Fedora
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-2016-2850 — 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-2016-2850 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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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
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