In 11.4-PRERELEASE before r360733 and 11.3-RELEASE before p13, improper mbuf handling in the kernel causes a use-after-free bug by sending IPv6 Hop-by-Hop options over the loopback interface. The use-after-free situation may result in unintended kernel behaviour including a kernel panic.
CVSS v4.0 Metrics
Exploitability
Attack VectorLocal
ComplexityLow
RequirementsPresent
PrivilegesLow
User InteractionNone
Threat
Exploit MaturityUnreported
Vulnerable System
ConfidentialityNone
IntegrityNone
AvailabilityHigh
Subsequent System
ConfidentialityNone
IntegrityNone
AvailabilityNone
Supplemental
SafetyNegligible
AutomatableYes
RecoveryAutomatic
Value DensityConcentrated
UrgencyMedium
Change Log
| Date | Source | Changes | Score |
|---|
| 2026-07-21 | nvd | AV: P→L, AC: H→L, PR: H→L, UI: A→N, VA: N→H | 0.0 → 1.9 |
| 2026-07-21 | cve.org | initial, patch: Unavailable | 0.0 |
Affected Software
| Vendor | Product | Version |
|---|
| freebsd | freebsd | 11.3 |
| freebsd | freebsd | 11.4 |
| n/a | FreeBSD | < p13 |
Published: 2021-03-26
