How severe is CVE-2021-26911?

CVE-2021-26911 has a CVSS 3.x base score of 7.4, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2021-26911 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (61st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-26911?

CVE-2021-26911 primarily affects Canarymail Canary Mail. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-26911?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-26911 published?

CVE-2021-26911 was published on 2021-02-17 and last updated on 2026-06-17.

CVE-2021-26911

CVE-2021-26911 is a high-severity vulnerability in Canarymail Canary Mail with a CVSS 3.x base score of 7.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-295.

Key facts

Severity: High (CVSS 3.x base score 7.4)
CVSS v2: 5.8
EPSS exploit prediction: 1% (61st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-295
Affected product: Canarymail Canary Mail
Published: 2021-02-17
Last modified: 2026-06-17

Description

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

Frequently asked questions

What is CVE-2021-26911?: core/imap/MCIMAPSession.cpp in Canary Mail before 3.22 has Missing SSL Certificate Validation for IMAP in STARTTLS mode.
How severe is CVE-2021-26911?: CVE-2021-26911 has a CVSS 3.x base score of 7.4, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2021-26911 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (61st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-26911?: CVE-2021-26911 primarily affects Canarymail Canary Mail. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-26911?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-26911 published?: CVE-2021-26911 was published on 2021-02-17 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:canarymail:canary_mail:3.20:*:*:*:*:iphone_os:*:*
cpe:2.3:a:canarymail:canary_mail:3.21:*:*:*:*:iphone_os:*:*
cpe:2.3:a:libmailcore:mailcore2:0.6.4:*:*:*:*:*:*:*

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