CVE-2026-55619 GOVCERT-LU CVE debrief

Who should care

SOC teams, email processing pipeline maintainers, and users of eml_parser should be aware of this vulnerability and take steps to update to version 3.0.2 or later. This vulnerability can disrupt SOC pipelines processing untrusted EML files, and updating eml_parser can prevent potential disruptions.

Why it matters

CVE-2026-55619 is a vulnerability in eml_parser that can cause a RecursionError when handling deeply nested CFWS comment constructs in email headers. SOC teams should prioritize updating eml_parser to version 3.0.2 or later to prevent potential disruptions from malformed EML files.

• Potential disruption of SOC pipelines processing untrusted EML files
• Need for exception handling from malformed or pathological messages
• Verification of eml_parser version in use
• Prioritization of updates to eml_parser version 3.0.2 or later

Technical summary

The eml_parser module prior to version 3.0.2 is vulnerable to a RecursionError when parsing deeply nested CFWS comment constructs in email headers. This can cause disruptions in SOC pipelines that process untrusted EML files. The vulnerability arises from the use of email.utils.getaddresses() to parse address-bearing e-mail headers, which does not handle deeply nested comments properly. The fix in version 3.0.2 addresses this issue by properly handling deeply nested comments. SOC teams should prioritize updating eml_parser to version 3.0.2 or later to prevent potential disruptions.

Defensive priority

SOC teams should prioritize updating eml_parser to version 3.0.2 or later to prevent potential disruptions from malformed EML files.

Recommended defensive actions

• Update eml_parser to version 3.0.2 or later
• Review and test EML file processing pipelines for potential disruptions
• Monitor for and handle exceptions from malformed or pathological messages
• Verify eml_parser version in use
• Prioritize updates to eml_parser version 3.0.2 or later
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, its impact, and the fix in eml_parser version 3.0.2. The vulnerability is caused by the use of email.utils.getaddresses() to parse address-bearing e-mail headers, which does not handle deeply nested comments properly. This can lead to a RecursionError when handling deeply nested CFWS comment constructs in email headers. The fix in version 3.0.2 addresses this issue.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.