In the crypt function, we attempt to null terminate a buffer using the size of the input salt without validating that the offset is within the buffer. This issue affects HHVM versions prior to 4.56.3, all versions between 4.57.0 and 4.80.1, all versions between 4.81.0 and 4.93.1, and versions 4.94.0, 4.95.0, 4.96.0, 4.97.0, 4.98.0.
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
ConfidentialityNone
IntegrityNone
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 | 4.6 → 6.9 |
| 2026-07-21 | nvd | AV: P→N, AC: H→L, PR: H→N, UI: A→N, VA: N→H | 0.0 → 4.6 |
| 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 |
|---|
| facebook | hhvm | ≥ 4.57.0, < 4.80.2 |
| facebook | hhvm | ≥ 4.81.0, < 4.93.2 |
| Facebook | HHVM | < 4.56.3 |
| facebook | hhvm | < 4.56.3 |
| Facebook | HHVM | 4.56.3 |
| Facebook | HHVM | 4.57.0 |
| Facebook | HHVM | 4.80.2 |
| Facebook | HHVM | 4.81.0 |
| Facebook | HHVM | 4.93.2 |
| facebook | hhvm | 4.94.0 |
| Facebook | HHVM | 4.94.0 |
| Facebook | HHVM | 4.94.1 |
| Facebook | HHVM | 4.95.0 |
| facebook | hhvm | 4.95.0 |
| Facebook | HHVM | 4.95.1 |
| facebook | hhvm | 4.96.0 |
| Facebook | HHVM | 4.96.0 |
| Facebook | HHVM | 4.96.1 |
| facebook | hhvm | 4.97.0 |
| Facebook | HHVM | 4.97.0 |
| Facebook | HHVM | 4.97.1 |
| Facebook | HHVM | 4.98.0 |
| facebook | hhvm | 4.98.0 |
| Facebook | HHVM | 4.98.1 |
Published: 2021-03-10
