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PatchSiren cyber security CVE debrief

CVE-2016-3995 Cryptopp CVE debrief

Crypto++ versions before 5.6.4 are affected by a side-channel weakness in Rijndael encryption and decryption paths. According to NVD, compiler optimization may remove timing-attack protection in Rijndael::Enc::ProcessAndXorBlock and Rijndael::Dec::ProcessAndXorBlock, which can expose confidential information to timing attacks.

Vendor
Cryptopp
Product
Crypto++
CVSS
HIGH 7.5
CISA KEV
Not listed in stored evidence
Original CVE published
2017-02-13
Original CVE updated
2026-05-13
Advisory published
2017-02-13
Advisory updated
2026-05-13

Who should care

Developers and operators using Crypto++ before 5.6.4, especially in applications that rely on Rijndael/AES for protecting secret data and expect constant-time behavior.

Technical summary

NVD identifies CVE-2016-3995 as a confidentiality issue in Crypto++ (cryptopp) before 5.6.4. The vulnerable code paths are Rijndael::Enc::ProcessAndXorBlock and Rijndael::Dec::ProcessAndXorBlock. The concern is that timing-attack protection may be optimized out by the compiler, undermining side-channel resistance and potentially allowing attackers to infer sensitive information through timing analysis.

Defensive priority

High. This is a confidentiality-focused cryptographic side-channel issue affecting a widely used primitive and should be remediated promptly wherever affected Crypto++ versions are deployed.

Recommended defensive actions

  • Upgrade Crypto++ to version 5.6.4 or later.
  • Audit applications and dependencies to confirm whether Crypto++ is used for Rijndael/AES operations.
  • Rebuild affected software after upgrading to ensure the fixed library is linked and deployed.
  • Review compiler and build settings for cryptographic code paths to make sure intended constant-time protections are preserved.
  • Validate remediation against vendor and project guidance referenced in the NVD record and project issue tracker.

Evidence notes

The NVD record states that timing attack protection in Rijndael::Enc::ProcessAndXorBlock and Rijndael::Dec::ProcessAndXorBlock in Crypto++ before 5.6.4 may be optimized out by the compiler, enabling timing attacks. NVD lists affected versions up to and including 5.6.3. Supporting references include the Crypto++ issue tracker and an OSS-security mailing list post dated 2016-04-11, which indicate earlier public discussion and patch context, but the CVE publication date used here is 2017-02-13.

Sources and references

Verified primary and authoritative sources

  • CVE-2016-3995 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2016-3995

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2016-3995 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2016-3995

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.