Loading vulnerability…
CVE-2026-23829 is an SMTP header injection vulnerability in Mailpit, an email testing tool and API for developers. Versions prior to 1.28.3 insufficiently validate SMTP envelope addresses supplied via the MAIL FROM and RCPT TO commands. The vulnerable address-validation regular expression fails to properly exclude carriage return and newline control characters when used inside a character class, allowing an attacker to include carriage return characters in an email address. As a result, crafted SMTP input can inject arbitrary headers into generated message content or corrupt existing headers during message construction and storage.
Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
What an attacker gets, and what they’ve been doing with it.
Received headers. This can produce malformed stored email content, undermine message integrity, and potentially affect downstream systems that export, parse, relay, or otherwise process the resulting messages. The issue may also enable corruption of stored data and parsing failures in the UI or API, creating limited denial-of-service or data integrity impacts in environments that accept untrusted SMTP input.If you can’t patch tonight, do this now.
Patch, then assume compromise.
MAIL FROM and RCPT TO, specifically ensuring carriage return, newline, and other control characters are excluded from the accepted address portion.No valid public exploits. Mallory filtered out 2 candidates as fakes, detection scripts, or README-only repos.
All candidate exploits were filtered out by Mallory's validation.
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
6 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.