Vulnerability in eml_parser (CVE-2026-55619)
Summary
Vulnerability in eml_parser (CVE-2026-55619). Risk of unauthorized operations or information disclosure. Exploitable via eml_parser. Mitigation: upgrade to 3.0.2 or later.
Original description
The description as published by the source.
Summary
eml_parser uses the email.utils.getaddresses() function from the CPython standard library to parse e-mail headers that contain e-mail addresses (such as To, Cc, Bcc, From, Reply-To, Sender, ...). When the input header contains a deeply nested CFWS (comment / folding white space) construct, the recursive descent parser in the standard library exhausts the call stack. The resulting RecursionError is not caught by eml_parser, so the exception propagates and aborts parsing of the whole message.
Impact
SOC pipelines use eml_parser to process untrusted e-mails. An attacker can easily create an eml file that will trigger the RecursionError during parsing.
The impact is mitigated by the fact that there are various other situations in which eml_parser will raise an exception when attempting to parse a malformed or pathological eml file. In particular, very deeply nested multipart e-mails also result in a RecursionError being raised by the library voluntarily. Therefore, systems relying on eml_parser already need to detect and handle errors emanating from the library in an appropriate way.
Workarounds
The issue can be avoided by wrapping the call to eml_parser.decode_email or eml_parser.decode_email_bytes in a try/except construct.
Patches
Since version 3.0.2, eml_parser will catch the error in the standard library parser and fall back to a simpler parser based on a regular expression.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-55619 has been found in eml_parser.
Attackers can target a specific entry point like eml_parser over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 5.3/10.
What to do: upgrade eml_parser to 3.0.2 or later.
If unsure, ask your IT team or search "eml_parser CVE-2026-55619" on the vendor's site.
CVE-2026-55619 (eml_parser) — CWE-770 / CVSS v3 5.3
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: eml_parser / Bcc / From / Sender
Patched: 3.0.2 — apply immediately
Workaround: The issue can be avoided by wrapping the call to eml_parser.decode_email or eml_parser.decode_email_bytes in a try/except construct.
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-770) exists in eml_parser. Attackers reach the vulnerable code path via eml_parser without authentication.
Check the vendor advisory for the affected versions of eml_parser. Attack surface: eml_parser / Bcc / From / Sender.
Severity: Medium (CVSS 5.3/10). Risk of unauthorized operations or information disclosure.
Update to 3.0.2.
Workaround: The issue can be avoided by wrapping the call to eml_parser.decode_email or eml_parser.decode_email_bytes in a try/except construct.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'eml_parser' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'eml_parser' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
eml_parserを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply temporary workaround mitigate
The issue can be avoided by wrapping the call to `eml_parser.decode_email` or `eml_parser.decode_email_bytes` in a `try/except` construct.パッチが適用されるまでの応急処置として、The issue can be avoided by wrapping the call to
eml_parser.decode_emailoreml_parser.decode_email_bytesin atry/exceptconstruct. を実施。回避策の副作用 (機能低下) を確認した上で。 -
3Apply patch patch
Upgrade eml_parser to 3.0.2ステージング環境で 3.0.2 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
4Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。