CVE-2016-9920

Exp

steps/mail/sendmail.inc in Roundcube before 1.1.7 and 1.2.x before 1.2.3, when no SMTP server is configured and the sendmail program is enabled, does not properly restrict the use of custom envelope-from addresses on the sendmail command line, which allows remote authenticated users to execute arbitrary code via a modified HTTP request that sends a crafted e-mail message.

Published: 2016-12-08 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2016-9920 is rated High Exploit Risk (72.2/100): CVSS High severity, with high exploitation likelihood (EPSS 5.62%, 92th percentile). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

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

Public exploit references (Exploit-DB) for CVE-2016-9920

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2016-9920

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 38.30% 5.62% -32.68%
2 2026-04-01 44.83% 38.30% -6.53%
3 2025-07-20 — 44.83% —

Full EPSS history (13 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2016-9920

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:H/PR:L/UI:N/S:U/C:H/I:H/A:H 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:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
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:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.6 5.9 [email protected]
6.0 2.0 MEDIUM
AV:N/AC:M/Au:S/C:P/I:P/A:P 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:S)
A single authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 6.8 6.4 [email protected]

Weakness enumeration for CVE-2016-9920

OS Trackers for CVE-2016-9920

vendor priority summary link
debian not yet assigned CVE-2016-9920 not yet assigned priority: Debian including 1 source packages (roundcube), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2016-9920
gentoo normal CVE-2016-9920: 1 GLSA(s) (201612-44), 1 atom(s) (mail-client/roundcube); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2016-9920
ubuntu medium CVE-2016-9920 medium priority: Ubuntu including 1 source packages (roundcube), 23 status rows across 23 suites (artful, bionic, cosmic, disco, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, precise, questing, trusty, upstream, xenial, yakkety, zesty): not-affected 19, released 2, DNE 1, ignored 1. https://ubuntu.com/security/CVE-2016-9920

Affected software / configurations for CVE-2016-9920

Vendor Product Version Raw CPE
roundcube webmail <= 1.1.6 cpe:2.3:a:roundcube:webmail:*:*:*:*:*:*:*:*
roundcube webmail 1.2.0 cpe:2.3:a:roundcube:webmail:1.2.0:*:*:*:*:*:*:*
roundcube webmail 1.2.1 cpe:2.3:a:roundcube:webmail:1.2.1:*:*:*:*:*:*:*
roundcube webmail 1.2.2 cpe:2.3:a:roundcube:webmail:1.2.2:*:*:*:*:*:*:*

References for CVE-2016-9920

cvelogic Threat Intelligence