CVE-2016-4842

Cybozu Mailwise before 5.4.0 allows remote attackers to obtain information on when an email is read.

Published: 2017-04-20 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2016-4842 is rated Moderate Risk (43.7/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.59%). EPSS rose +1.23% over the last day, indicating growing attacker interest. 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-2016-4842

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 0.36% 1.59% +1.23%
2 2025-03-17 0.18% 0.36% +0.18%
3 2023-03-07 — 0.18% —

Full EPSS history (4 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2016-4842

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
4.3 3.0 MEDIUM
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:L/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:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 1.4 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/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:M)
Exploitation needs some favorable conditions, but not exceptional ones.
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.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2016-4842

Affected software / configurations for CVE-2016-4842

Vendor Product Version Raw CPE
cybozu mailwise 5.0.0 cpe:2.3:a:cybozu:mailwise:5.0.0:*:*:*:*:*:*:*
cybozu mailwise 5.0.1 cpe:2.3:a:cybozu:mailwise:5.0.1:*:*:*:*:*:*:*
cybozu mailwise 5.0.4 cpe:2.3:a:cybozu:mailwise:5.0.4:*:*:*:*:*:*:*
cybozu mailwise 5.0.5 cpe:2.3:a:cybozu:mailwise:5.0.5:*:*:*:*:*:*:*
cybozu mailwise 5.0.6 cpe:2.3:a:cybozu:mailwise:5.0.6:*:*:*:*:*:*:*
cybozu mailwise 5.1.0 cpe:2.3:a:cybozu:mailwise:5.1.0:*:*:*:*:*:*:*
cybozu mailwise 5.1.1 cpe:2.3:a:cybozu:mailwise:5.1.1:*:*:*:*:*:*:*
cybozu mailwise 5.1.2 cpe:2.3:a:cybozu:mailwise:5.1.2:*:*:*:*:*:*:*
cybozu mailwise 5.1.4 cpe:2.3:a:cybozu:mailwise:5.1.4:*:*:*:*:*:*:*
cybozu mailwise 5.2.0 cpe:2.3:a:cybozu:mailwise:5.2.0:*:*:*:*:*:*:*
cybozu mailwise 5.2.1 cpe:2.3:a:cybozu:mailwise:5.2.1:*:*:*:*:*:*:*
cybozu mailwise 5.3.0 cpe:2.3:a:cybozu:mailwise:5.3.0:*:*:*:*:*:*:*
cybozu mailwise 5.3.1 cpe:2.3:a:cybozu:mailwise:5.3.1:*:*:*:*:*:*:*
cybozu mailwise 5.3.2 cpe:2.3:a:cybozu:mailwise:5.3.2:*:*:*:*:*:*:*

References for CVE-2016-4842

URL Tags
http://jvn.jp/en/jp/JVN02576342/index.html Third Party Advisory VDB Entry
http://jvndb.jvn.jp/en/contents/2016/JVNDB-2016-000136.html Third Party Advisory VDB Entry
http://www.securityfocus.com/bid/92460 Third Party Advisory VDB Entry
https://support.cybozu.com/ja-jp/article/9606 Vendor Advisory
cvelogic Threat Intelligence