CVE-2016-3995

The timing attack protection in Rijndael::Enc::ProcessAndXorBlock and Rijndael::Dec::ProcessAndXorBlock in Crypto++ (aka cryptopp) before 5.6.4 may be optimized out by the compiler, which allows attackers to conduct timing attacks.

Published: 2017-02-13 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2016-3995 is rated Moderate Risk (57.6/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.86%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2016-3995

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 1.03% 1.86% +0.83%
2 2025-03-30 1.59% 1.03% -0.57%
3 2025-03-29 — 1.59% —

Full EPSS history (6 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2016-3995

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.0 HIGH
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2016-3995

OS Trackers for CVE-2016-3995

vendor priority summary link
debian not yet assigned CVE-2016-3995 not yet assigned priority: Debian including 1 source packages (libcrypto++), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2016-3995
ubuntu medium CVE-2016-3995 medium priority: Ubuntu including 1 source packages (libcrypto++), 9 status rows across 9 suites (artful, bionic, precise, trusty, upstream, wily, xenial, yakkety, zesty): not-affected 4, released 3, ignored 2. https://ubuntu.com/security/CVE-2016-3995

Affected software / configurations for CVE-2016-3995

Vendor Product Version Raw CPE
cryptopp crypto\+\+ <= 5.6.3 cpe:2.3:a:cryptopp:crypto\+\+:*:*:*:*:*:*:*:*

References for CVE-2016-3995

URL Tags
http://www.openwall.com/lists/oss-security/2016/04/11/2 Mailing List Patch Third Party Advisory
http://www.securityfocus.com/bid/85975 Third Party Advisory VDB Entry
https://github.com/weidai11/cryptopp/issues/146 Issue Tracking Patch Third Party Advisory
cvelogic Threat Intelligence