CVE-2026-55620Network attack vector

Service interruption via quadratic Received-comment stripping

Published Aug 25, 2026 · Updated Aug 26, 2026

Algorithmic complexity in GOVCERT.LU eml_parser before 3.0.2 allows remote attackers to saturate workers via crafted EML files. The eml_parser.routing.noparenthesis function repeatedly applies a regular expression while stripping nested CFWS comments from Received headers, causing processing time to grow quadratically with nesting depth. Exposure requires an application to parse attacker-supplied email; affected workers can sustain CPU saturation and queue backpressure, and synchronous pipelines can suffer service-level outages.

CVSS severity7.5
High
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Algorithmic complexity in GOVCERT.LU eml_parser before 3.0.2 allows remote attackers to saturate workers via crafted EML files. The eml_parser.routing.noparenthesis function repeatedly applies a regular expression while stripping nested CFWS comments from Received headers, causing processing time to grow quadratically with nesting depth. Exposure requires an application to parse attacker-supplied email; affected workers can sustain CPU saturation and queue backpressure, and synchronous pipelines can suffer service-level outages.

The record

CVE
CVE-2026-55620
Published
Aug 25, 2026
Updated
Aug 26, 2026
Vendor
GOVCERT.LU
Product
eml_parser
Classifications
CWE-1124, CWE-770, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 26, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 3.0.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

GOVCERT.LU · eml_parserversion=< 3.0.2

Published CVSS scores

7.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1124Excessively Deep Nesting
CWE-770Allocation of Resources Without Limits or Throttling
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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