Ruby vulnerabilities
Summary
It was discovered that Ruby's Net::IMAP library did not properly verify that Transport Layer Security (TLS) encryption was started after issuing a STARTTLS command. A remote attacker could possibly use this issue to perform a machine-in-the-middle attack and silently bypass TLS encryption. (CVE-2026-42246) It was also discovered that Ruby's Net::IMAP library did not validate string arguments passed to certain commands. A remote attacker could possibly use this issue to inject arbitrary IMAP commands. (CVE-2026-42257) Affected Ubuntu releases: 18.04, 16.04. CVEs: CVE-2026-42257, CVE-2026-42246.
- Ubuntu 18.04
- Ubuntu 16.04
Official advisory · medium-confidence parse· fetched 3 hours ago·verify at source
Mitigation checklist
- Apply available updates: `sudo apt update && sudo apt upgrade` (a standard system update installs the fix).
Official advisory · medium-confidence parse· fetched 3 hours ago·verify at source
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