CVE-2026-124016

6.9 MEDIUM 0.6% exploit odds Fix listed Denial of service

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in. Limited direct impact.
Exploit odds: 0.6% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-11-06 18:38 UTC ReservedThe CVE id was reserved by its CNA
2026-11-10 20:19 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-11-12 21:36 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.6% in the next 30 days (EPSS).
Severity: 6.9 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-11-10 20:19 UTC
Last modified: 2026-11-12 21:36 UTC
Exploit probability: 0.6% · EPSS, next 30 days
Weakness: CWE-407
Record status: Deferred

Attack profile CVSS 4.0 · 6.9

Attack vector: Network
Complexity: Low
Attack requirements: None
Privileges needed: None
User interaction: None
Confidentiality: None
Integrity: None
Availability: Low

Raw 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-124016.md and follow it. Check whether this project is affected by CVE-2026-124016. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record