A newly reported high-impact security flaw in BIND 9, one of the most widely deployed DNS server implementations, could allow attackers to disrupt DNS operations remotely. By sending specially crafted DNS data, an attacker may cause the DNS service to stop unexpectedly.
The issue is tracked as CVE-2025-13878 and affects both DNS resolvers and authoritative name servers.
How the Issue Occurs
The vulnerability lies in how BIND 9 processes certain DNS record types. Specifically, malformed BRID and HHIT records are not handled safely by the named process.
If a DNS server receives a request containing corrupted versions of these records, the service may terminate, resulting in a denial-of-service condition and temporary loss of name resolution.
This flaw is notable because it:
- Can be exploited remotely over the network
- Does not require authentication or user interaction
- Affects internet-facing DNS infrastructure
- Can impact availability of dependent services
Although the vulnerability does not allow data theft or code execution, DNS outages alone can cause significant operational disruption.
Technical Overview
| Item | Information |
|---|---|
| CVE | CVE-2025-13878 |
| Affected Component | BIND 9 (named daemon) |
| Vulnerability Class | Denial of Service |
| Attack Method | Malformed DNS records |
| Access Required | None |
| CVSS Score | 7.5 (High) |
Versions Impacted and Fixes
Administrators should verify their installed versions and upgrade where necessary.
| BIND Release Line | Affected Versions | Fixed Version |
|---|---|---|
| BIND 9 | 9.18.40 – 9.18.43 | 9.18.44 |
| BIND 9 | 9.20.13 – 9.20.17 | 9.20.18 |
| BIND 9 | 9.21.12 – 9.21.16 | 9.21.17 |
| BIND SPE | 9.18.40-S1 – 9.18.43-S1 | 9.18.44-S1 |
| BIND SPE | 9.20.13-S1 – 9.20.17-S1 | 9.20.18-S1 |
ISC publicly announced this vulnerability in late January 2026 after completing a coordinated disclosure process with the reporting researcher. At the time of disclosure, no confirmed exploitation had been observed in the wild.
However, no temporary mitigations or configuration-based protections are available, making patching the only effective way to address the issue. This gives organizations a limited but important opportunity to update affected systems before active exploitation begins.
What Administrators Should Do
Organizations running BIND 9 should:
- Upgrade to patched releases as soon as possible
- Review exposure of publicly reachable DNS servers
- Monitor DNS processes for abnormal crashes or restarts
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