CVE-2018-9860
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 · uneditedAn issue was discovered in Botan 1.11.32 through 2.x before 2.6.0. An off-by-one error when processing malformed TLS-CBC ciphertext could cause the receiving side to include in the HMAC computation exactly 64K bytes of data following the record buffer, aka an over-read. The MAC comparison will subsequently fail and the connection will be closed. This could be used for denial of service. No information leak occurs.
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 confidenceAn off-by-one error in Botan library's TLS-CBC decryption allows a malformed ciphertext to cause a 64KB over-read beyond the record buffer. The extra data is included in HMAC computation, causing MAC verification to fail and connections to be terminated, enabling denial of service.
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>= 1.11.32, < 2.6.0CVSS 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.
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Identify installed Botan library versionQuery the Botan library version via pkg-config, dpkg, rpm, or by calling Botan::version_major() / Botan::version_minor() / Botan::version_patch() in code. Check libbotan.so* files or headers for version strings.Affected if The installed version is found to be greater than or equal to 1.11.32 but less than 2.6.0
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Locate Botan library files on the systemSearch for libbotan* files in /usr/lib, /usr/local/lib, or application-dependent library paths using 'find /usr -name "libbotan*"' or similar.Affected if Botan library binaries exist and the version check above confirms an affected version
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Determine if TLS-CBC cipher suites are in useReview application configuration, TLS server/client settings, or logs for active cipher suites. Check if CBC-mode TLS ciphers (such as TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA) are enabled or negotiated.Affected if TLS connections use CBC-mode cipher suites, as the vulnerability exists specifically in the TLS-CBC decryption code path
The environment is affected if a Botan library version between 1.11.32 and 2.6.0 (exclusive) is present and TLS-CBC decryption is performed.
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 data2.6.0
Upgrade Botan to version 2.6.0 or later. Applications using the affected library versions should update their Botan dependency and verify TLS functionality after patching.
- Consultation3.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,416.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-9860 — 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-2018-9860 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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