November 14, 2026

CVE Watchtower

CVE-2026-125756postalsys postal-mime

NVD

Vulnerability Summary

postal-mime before 4.2.1 contains a parser differential vulnerability in its address parser that truncates the domain at folding whitespace or comments preceding a dot. Remote attackers can craft From headers that pass SPF/DKIM/DMARC alignment for their own subdomain while PostalMime.parse() reports a spoofed victim sender address.
Severity Level
HIGH(8.2)
Published Date
Nov 10, 2026
Last Modified
Nov 10, 2026
Exploitation Status
No confirmed exploitation yet
EPSS Score (30-Day)
0.39%Probability
Root Weakness (CWE)
CWE-436 ↗
See the MITRE CWE entry for the full definition of this weakness.
CVSS v4.0 Base Metrics — Score 8.2 (HIGH)
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
Attack VectorNetwork
Attack ComplexityHigh
Attack RequirementsPresent
Privileges RequiredNone
User InteractionNone
Confidentiality (Vulnerable System)None
Integrity (Vulnerable System)High
Availability (Vulnerable System)None
Confidentiality (Subsequent System)None
Integrity (Subsequent System)None
Availability (Subsequent System)None
Show CVSS v3.x metrics (score 5.9)
CVSS v3.1 Base Metrics — Score 5.9 (MEDIUM)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Attack VectorNetwork
Attack ComplexityHigh
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityNone
IntegrityHigh
AvailabilityNone

Affected & Patched Versions

Affected Versions
  • postalsys postal-mime < 4.2.1
Patched Versions
  • postalsys postal-mime 4.2.1

What to do

Plan remediation soon. No exploitation is confirmed yet, but the severity is high.

  1. Check whether you run postalsys postal-mime and which version.
  2. Update to a patched version listed above, then confirm the new version.

Timeline

  • Nov 10, 2026Published
  • Nov 10, 2026Record last modified

Score, severity and exploitation changes are tracked from the day Watchtower started logging them.

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External References

Data last checked: Nov 14, 2026 02:13 UTC