PatchTheCVECVE-2026-82854: Nodemailer before 8.0.4 is vulnerable to SMTP command injection through the unsanitized envelope.size paramete
CVE-2026-82854 is a critical-severity flaw (CVSS 9.8) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
Nodemailer before 8.0.4 is vulnerable to SMTP command injection through the unsanitized envelope.size parameter. When an application passes a custom envelope object with a size property containing CRLF characters to sendMail(), the value is concatenated into the SMTP MAIL FROM command (as SIZE=...) without sanitization, allowing injection of arbitrary SMTP commands such as RCPT TO to silently add attacker-controlled recipients. Exploitation requi
Why this priority
- Critical severity
- CISA SSVC: automatable with total technical impact
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 9.8 (Critical) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 2.0% (top 20%) |
| CISA exploited list | No |
| Weakness | CWE-93 |
| Published | 2026-08-31 |
| Last modified | 2026-10-08 |
Last updated 2026-10-08 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Timeline
- Published CVE record published
- Updated Record last modified
Exact fixes by distribution
Public exploits and detection
Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-82854?
No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.
Is CVE-2026-82854 being exploited?
CVE-2026-82854 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-82854 affect?
CVE-2026-82854 affects affected software. Severity is critical (CVSS 9.8). Nodemailer before 8.0.4 is vulnerable to SMTP command injection through the unsanitized envelope.size parameter. When an application passes a custom envelope object with a size property containing CRLF characters to sendMail(), the value is
How urgent is CVE-2026-82854?
Priority 62/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action