SB2025112059 - Red Hat Enterprise Linux 9 update for bind
Published: November 20, 2025
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 3 secuirty vulnerabilities.
1) Reliance on Reverse DNS Resolution for a Security-Critical Action (CVE-ID: CVE-2021-25220)
The vulnerability allows a remote attacker to poison DNS cache.
The vulnerability exists due to an error in DNS forwarder implementation. When using forwarders, bogus NS records supplied by, or via, those forwarders may be cached and used by named if it needs to recurse for any reason, causing it to obtain and pass on potentially incorrect answers. The cache could become poisoned with incorrect records leading to
queries being made to the wrong servers, which might also result in
false information being returned to clients.
2) Insufficient verification of data authenticity (CVE-ID: CVE-2025-40778)
The vulnerability allows a remote attacker to poison DNS cache.
The vulnerability exists due to insufficient verification of data authenticity when accepting records from answers. A remote attacker can inject forged data into the cache leading to DNS cache poisoning.
3) Predictable Seed in Pseudo-Random Number Generator (PRNG) (CVE-ID: CVE-2025-40780)
The vulnerability allows a remote attacker to poison DNS cache.
The vulnerability exists due to weakness in the Pseudo Random Number Generator (PRNG). A remote attacker can predict the source port and query ID that BIND will use and perform DNS cache poisoning attacks.
Remediation
Install update from vendor's website.