VDB
ALPINE-CVE-2025-5994
ALPINE-CVE-2025-5994
PUBLISHED
CVSS 8.699999809265137 HIGH
A multi-vendor cache poisoning vulnerability named 'Rebirthday Attack' has been discovered in caching resolvers that support EDNS Client Subnet (ECS). Unbound is also vulnerable when compiled with ECS support, i.e., '--enable-subnet', AND configured to send ECS information along with queries to upstream name servers, i.e., at least one of the 'send-client-subnet', 'client-subnet-zone' or 'client-subnet-always-forward' options is used. Resolvers supporting ECS need to segregate outgoing queries to accommodate for different outgoing ECS information. This re-opens up resolvers to a birthday paradox attack (Rebirthday Attack) that tries to match the DNS transaction ID in order to cache non-ECS poisonous replies.
Risk Scores
CVSS v4.0
8.699999809265137
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:U/V:C/RE:X/U:X
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Alpine:v3.23 | unbound | 1.17.1-r1, 1.17.1-r0, 1.17.0-r1 |
| Alpine:v3.19 | unbound | 1.9.1-r0, 0, 1.10.0-r0 |
| Alpine:v3.21 | unbound | 1.9.6-r0, 0, 1.10.0-r0 |
| Alpine:v3.22 | unbound | 1.6.6-r0, 1.7.0-r1, 1.6.4-r0 |
| Alpine:v3.20 | unbound | 1.4.10-r2, 1.13.0-r1, 1.9.6-r0 |
Timeline
- Jul 16, 2025 CVE Published
- Dec 3, 2025 CVE Updated
- Apr 30, 2026 Distribution Patch