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.
An official patch is available. Apply the patch as soon as possible.
CVSS v4.0 Metrics
Exploitability
Attack VectorNetwork
ComplexityLow
RequirementsPresent
PrivilegesNone
User InteractionNone
Threat
Exploit MaturityPoC
Vulnerable System
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
Subsequent System
ConfidentialityNone
IntegrityNone
AvailabilityNone
Supplemental
SafetyNegligible
AutomatableYes
RecoveryAutomatic
Value DensityConcentrated
UrgencyMedium
Patch StatusOfficial Patch
Change Log
| Date | Source | Changes | Score |
|---|
| 2026-07-21 | PoC | E: U→P | 7.2 → 8.2 |
| 2026-07-21 | nvd | AV: P→N, AC: H→L, PR: H→N, UI: A→N, VC: N→H, VI: N→H, VA: N→H | 0.0 → 7.2 |
| 2026-07-21 | nvd | patch: Unavailable→Official Patch | 0.0 → 0.0 |
| 2026-07-21 | cve.org | initial, patch: Unavailable | 0.0 |
Affected Software
| Vendor | Product | Version |
|---|
| phpmailer_project | phpmailer | ≥ 6.1.8, ≤ 6.4.0 |
| wordpress | wordpress | ≥ 4.4, < 4.4.25 |
| wordpress | wordpress | ≥ 5.5, < 5.5.5 |
| wordpress | wordpress | ≥ 4.5, < 4.5.24 |
| wordpress | wordpress | ≥ 5.6, < 5.6.4 |
| wordpress | wordpress | ≥ 4.6, < 4.6.21 |
| wordpress | wordpress | ≥ 5.7, < 5.7.2 |
| wordpress | wordpress | ≥ 4.7, < 4.7.21 |
| wordpress | wordpress | ≥ 3.7, < 3.7.36 |
| wordpress | wordpress | ≥ 4.8, < 4.8.17 |
| wordpress | wordpress | ≥ 3.8, < 3.8.36 |
| wordpress | wordpress | ≥ 4.9, < 4.9.18 |
| wordpress | wordpress | ≥ 3.9, < 3.9.34 |
| wordpress | wordpress | ≥ 5.0, < 5.0.13 |
| wordpress | wordpress | ≥ 4.0, < 4.0.33 |
| wordpress | wordpress | ≥ 5.1, < 5.1.10 |
| wordpress | wordpress | ≥ 4.1, < 4.1.33 |
| wordpress | wordpress | ≥ 5.2, < 5.2.11 |
| wordpress | wordpress | ≥ 4.2, < 4.2.30 |
| wordpress | wordpress | ≥ 5.3, < 5.3.8 |
| wordpress | wordpress | ≥ 4.3, < 4.3.26 |
| wordpress | wordpress | ≥ 5.4, < 5.4.6 |
Published: 2021-04-28
