CVE-2021-26911

Exp

core/imap/MCIMAPSession.cpp in Canary Mail before 3.22 has Missing SSL Certificate Validation for IMAP in STARTTLS mode.

Published: 2021-02-17 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-26911 is rated High Exploit Risk (66.7/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.09%). 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-2021-26911

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

Exploit prediction scoring system (EPSS) score for CVE-2021-26911

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 0.28% 1.09% +0.81%
2 2025-03-30 0.57% 0.28% -0.29%
3 2025-03-29 — 0.57% —

Full EPSS history (11 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-26911

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.4 3.1 HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/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:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
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:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 5.2 [email protected]
5.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/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:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 8.6 4.9 [email protected]

Weakness enumeration for CVE-2021-26911

Affected software / configurations for CVE-2021-26911

Vendor Product Version Raw CPE
canarymail canary_mail 3.20 cpe:2.3:a:canarymail:canary_mail:3.20:*:*:*:*:iphone_os:*:*
canarymail canary_mail 3.21 cpe:2.3:a:canarymail:canary_mail:3.21:*:*:*:*:iphone_os:*:*
libmailcore mailcore2 0.6.4 cpe:2.3:a:libmailcore:mailcore2:0.6.4:*:*:*:*:*:*:*

References for CVE-2021-26911

cvelogic Threat Intelligence