postal-mime before 4.2.1 contains an algorithmic complexity denial of service vulnerability that allows unauthenticated remote attackers to cause excessive CPU consumption in the PostalMime.processLine() function by crafting deeply nested multipart email messages with boundary lines sharing long prefixes with open boundaries. Attackers can deliver a malicious email with nesting up to the default maxNestingDepth of 256, causing per-line parsing cost to scale as O(depth x shared prefix length) and blocking the Node.js event loop for seconds per message.
History

Thu, 12 Nov 2026 20:30:00 +0000

Type Values Removed Values Added
First Time appeared Postalsys
Postalsys postal-mime
Vendors & Products Postalsys
Postalsys postal-mime

Thu, 12 Nov 2026 01:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Tue, 10 Nov 2026 19:30:00 +0000

Type Values Removed Values Added
Description postal-mime before 4.2.1 contains an algorithmic complexity denial of service vulnerability that allows unauthenticated remote attackers to cause excessive CPU consumption in the PostalMime.processLine() function by crafting deeply nested multipart email messages with boundary lines sharing long prefixes with open boundaries. Attackers can deliver a malicious email with nesting up to the default maxNestingDepth of 256, causing per-line parsing cost to scale as O(depth x shared prefix length) and blocking the Node.js event loop for seconds per message.
Title postal-mime < 4.2.1 Algorithmic Complexity DoS via processLine
Weaknesses CWE-407
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'}

cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published: 2026-11-10T19:22:30.485Z

Updated: 2026-11-10T21:03:45.609Z

Reserved: 2026-11-06T18:38:38.544Z

Link: CVE-2026-124016

cve-icon Vulnrichment

Updated: 2026-11-10T21:03:40.222Z

cve-icon NVD

Status : Received

Published: 2026-11-10T20:19:04.337

Modified: 2026-11-10T21:19:06.983

Link: CVE-2026-124016

cve-icon Redhat

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