CVE-2020-36326

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 3.1%, top 14% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Trending — 3 sources updated this week
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 3%CVSS: 9.8Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

PHPMailer 6.1.8 through 6.4.0 allows object injection through Phar Deserialization via addAttachment with a UNC pathname. NOTE: this is similar to CVE-2018-19296, but arose because 6.1.8 fixed a functionality problem in which UNC pathnames were always considered unreadable by PHPMailer, even in safe contexts. As an unintended side effect, this fix eliminated the code that blocked addAttachment exploitation.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
50(Track)
EG Risk 50/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation3% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
86.4%
KEV
Not listed

Published

April 28, 2021

Last Modified

November 21, 2024

Advisory Details (3)

Auto-updated Jun 8, 2026
Patch available. Sources: github_commit.
generic

[SECURITY] Fedora 34 Update: php-phpmailer6-6.4.1-1.fc34 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KPU66INRFY5BQ3ESVPRUXJR4DXQAFJVT/
generic

[SECURITY] Fedora 33 Update: php-phpmailer6-6.4.1-1.fc33 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3B5WDPGUFNPG4NAZ6G4BZX43BKLAVA5B/
github_commit Patch Available

commit e2e07a355ee8 (PHPMailer/PHPMailer)

Patch available: PHPMailer/PHPMailer v6.2.0 (contains commit e2e07a355ee8)

https://github.com/PHPMailer/PHPMailer/commit/e2e07a355ee8ff36aba21d0242c5950c56e4c6f9

Vendor Advisories for CVE-2020-36326(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
Packagist(1)
PackageVulnerable rangeFixed inDependents
phpmailer/phpmailerv6.1.8, v6.2.0, v6.3.0, v6.4.06.4.1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 14× in last 7d / 47× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-23 14:15 UTCEPSS rescore
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  3. 2026-07-23 01:53 UTCEG score recompute
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Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2020-36326?
CVE-2020-36326 is a critical vulnerability published on April 28, 2021. PHPMailer 6.1.8 through 6.4.0 allows object injection through Phar Deserialization via addAttachment with a UNC pathname. NOTE: this is similar to CVE-2018-19296, but arose because 6.1.8 fixed a functionality problem in which UNC pathnames were always considered unreadable by PHPMailer, even in…
When was CVE-2020-36326 disclosed?
CVE-2020-36326 was first published in the National Vulnerability Database on April 28, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2020-36326 actively exploited?
CVE-2020-36326 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 86.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2020-36326?
CVE-2020-36326 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2020-36326?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2020-36326, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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