CVE-2026-32877
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 is a C++ cryptography library. From version 2.3.0 to before version 3.11.0, during SM2 decryption, the code that checked the authentication code value (C3) failed to check that the encoded value was of the expected length prior to comparison. An invalid ciphertext can cause a heap over-read of up to 31 bytes, resulting in a crash or potentially other undefined behavior. This issue has been patched in version 3.11.0.
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 confidenceIn Botan versions 2.3.0 through 3.10.x, the SM2 decryption code fails to validate the length of the C3 authentication tag before comparing it against the ciphertext. This allows a malformed ciphertext to trigger a heap over-read of up to 31 bytes, potentially causing denial of service or undefined behavior.
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>= 2.3.0, < 3.11.0CVSS 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
- Low
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/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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Locate the Botan library installationFind where the Botan library is installed on your system. Check common locations such as /usr/lib/, /usr/local/lib/, or project dependency directories. Look for files named libbotan.* or header files like botan/version.h.Affected if Botan library is present on the system
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Determine the installed Botan versionQuery the library version using pkg-config --modversion botan, or inspect the BOTAN_VERSION_STRING macro from botan/version.h. If using a package manager, run dpkg -l libbotan* or rpm -qi botan.Affected if Version is >= 2.3.0 and < 3.11.0 (i.e., falls within the affected range)
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Identify if SM2 decryption is being usedReview application source code or configuration to determine if SM2 decryption functions are invoked. Search for SM2-related API calls such as botan_sm2_decrypt, or examine cipher configurations that specify SM2 as the algorithm.Affected if SM2 decryption functionality is actively used in the application
If the installed Botan version is 2.3.0 through 3.10.x and the application performs SM2 decryption operations, the environment is vulnerable to CVE-2026-32877.
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.
dbcve · scoped3.11.0
Upgrade Botan library to version 3.11.0 or later. If upgrading is not feasible, implement input validation on SM2 ciphertexts before passing them to the decryption routine to ensure the C3 component matches expected length constraints.
3.11.0
- 1. Identify the current Botan library version in your project by checking your dependency manifest (e.g., package.json, requirements.txt, conanfile.txt, or package manager lock file).
- 2. Update the Botan dependency to version 3.11.0 or later using your project's package manager (e.g., pip install botan==3.11.0, conan install botan/3.11.0, or equivalent).
- 3. Rebuild and recompile any projects that link against the Botan library to ensure the new version is incorporated.
- 4. Run your test suite to verify the application functions correctly after the upgrade.
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-32877 — 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-2026-32877 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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- Version or environment caveats, and links to real fixes
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