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Vulnerability record · CVE-2021-26911 · published 17 February 2021

CVE-2021-26911: Canarymail canary mail improper certificate validation vulnerability

Canarymail · Canary Mail

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

7.4 CVSS 3.1 High EPSS 1.1% · top 36.0% CWE-295 · Improper certificate validation
7.4CVSS 3.1 base score, v2 5.8
1.1%EPSS exploitation probability, 30 days
NoNot in CISA KEV
2Affected product versions listed by NVD
12References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

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

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected products

2 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://www.openwall.com/lists/oss-security/2021/02/17/3 Mailing ListPatchThird Party Advisory
https://apps.apple.com/us/app/canary-mail/id1236045954 ProductThird Party Advisory
https://census-labs.com/news/2021/02/17/canary-mail-app-missing-certificate-validation-check-on-imap-starttls/ ExploitThird Party Advisory
https://census-labs.com/news/category/advisories/ Third Party Advisory
https://github.com/canarymail/mailcore2/commit/45acb4efbcaa57a20ac5127dc976538671fce018 PatchThird Party Advisory
https://www.openwall.com/lists/oss-security/2021/02/17/3 Mailing ListPatchThird Party Advisory
http://www.openwall.com/lists/oss-security/2021/02/17/3 Mailing ListPatchThird Party Advisory
https://apps.apple.com/us/app/canary-mail/id1236045954 ProductThird Party Advisory
https://census-labs.com/news/2021/02/17/canary-mail-app-missing-certificate-validation-check-on-imap-starttls/ ExploitThird Party Advisory
https://census-labs.com/news/category/advisories/ Third Party Advisory
https://github.com/canarymail/mailcore2/commit/45acb4efbcaa57a20ac5127dc976538671fce018 PatchThird Party Advisory
https://www.openwall.com/lists/oss-security/2021/02/17/3 Mailing ListPatchThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2021-26911), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.