Improper Enforcement of Behavioral Workflow Affecting net-imap package, versions <0.3.10>=0.4.0, <0.4.24>=0.5.0, <0.5.14>=0.6.0, <0.6.4
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-RUBY-NETIMAP-16420230
- published6 May 2026
- disclosed4 May 2026
- creditMasamune
Introduced: 4 May 2026
NewCVE-2026-42246 (opens in a new tab)How to fix?
Upgrade net-imap to version 0.3.10, 0.4.24, 0.5.14, 0.6.4 or higher.
Overview
Affected versions of this package are vulnerable to Improper Enforcement of Behavioral Workflow via the starttls function. An attacker can intercept and manipulate the communication by injecting a crafted response before the client completes sending the command, causing the connection to remain unencrypted and potentially exposing sensitive information in cleartext.
Note: This is only exploitable if the client does not explicitly verify the TLS status after attempting to initiate a secure connection.
Workaround
This vulnerability can be mitigated by explicitly verifying the TLS status using the tls_verified? method after initiating the secure connection, or by connecting directly to an implicit TLS port instead of using STARTTLS.