CVE-2016-8871
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 · uneditedIn Botan 1.11.29 through 1.11.32, RSA decryption with certain padding options had a detectable timing channel which could given sufficient queries be used to recover plaintext, aka an "OAEP side channel" attack.
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's RSA decryption implementation with OAEP padding contained a timing side-channel that leaked information about the plaintext through observable timing variations during decryption operations. An attacker with the ability to make many decryption queries could exploit this timing difference to gradually recover the plaintext, similar to Bleichenbacher-style padding oracle attacks.
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= 1.11.29= 1.11.30= 1.11.31= 1.11.32CVSS 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
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.0/AV:L/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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Identify installed Botan versionCheck the Botan library version through package manager, library file metadata, or inspect headers (botan/version.h) if the source is available. If using a binary distribution, check the library filename or embedded version resource.Affected if The installed version is 1.11.29, 1.11.30, 1.11.31, or 1.11.32
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Locate the Botan library in useFind the botan library file linked by your application using 'ldd' on Linux or dependency walker on Windows. Check build configuration or package manifest to confirm which Botan version is bundled.Affected if The application links to Botan versions 1.11.29 through 1.11.32
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Determine if RSA decryption with OAEP is implementedReview application source code for use of Botan's RSA_OAEP decryption API (look for 'RSA_OAEP', 'decrypt', or OAEP-related padding mode configurations). Check configuration files or runtime settings for RSA padding scheme.Affected if The application performs RSA decryption using OAEP padding mode with the vulnerable Botan version
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Check for exposed decryption interfaceDetermine if the application accepts or processes RSA-encrypted data from untrusted sources, as the attack requires making many decryption queries. Audit network-facing APIs or data processing pipelines that handle RSA-encrypted payloads.Affected if The application exposes an RSA decryption interface that allows an attacker to submit ciphertexts for decryption repeatedly
You are affected if your application uses Botan versions 1.11.29 through 1.11.32 AND performs RSA decryption with OAEP padding, especially if an attacker can make repeated decryption 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.
From vendor dataUpgrade Botan to version 1.11.33 or later where the timing leak was fixed. If upgrading is not immediately possible, consider using alternative padding schemes like PKCS#1 v1.5 if acceptable for the use case, or implement fixed-time decryption as a temporary workaround.
- Consultation2.0 h
- Implementation8.0 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 $4,480.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-8871 — 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-2016-8871 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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