CVE-2026-3104: ISC BIND 9 · Missing Release of Resource after Effective Lifetime
Affects ISC BIND 9Source CVE Database V5
Not known to be exploited · CVSS 7.5 High · fixed in 9.21.20 : patch ISC BIND 9 soon.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 0.7% chance of exploitation in 30 days – higher than 53% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 9.21.20, 9.21.0, 9.20.21 +1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade isc/bind9 to 9.21.20, 9.21.0, 9.20.21 or 9.20.0.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| ISCBIND 9 | Affected
| Fixed in– |
GitHubisc/bind9pkg:github/isc/bind9Other threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
The Red Hat advisories reference this CVE but do not explicitly confirm a fix or update addressing it. If you cannot patch yet, consider limiting exposure of vulnerable BIND resolvers to untrusted networks to reduce risk.
Description
A specially crafted domain can be used to cause a memory leak in a BIND resolver simply by querying this domain. This issue affects BIND 9 versions 9.20.0 through 9.20.20, 9.21.0 through 9.21.19, and 9.20.9-S1 through 9.20.20-S1. BIND 9 versions 9.18.0 through 9.18.46 and 9.18.11-S1 through 9.18.46-S1 are NOT affected.
References
- kb.isc.org/docs/cve-2026-3104 (opens in a new tab)
- downloads.isc.org/isc/bind9/9.20.21 (opens in a new tab)
- downloads.isc.org/isc/bind9/9.21.20 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-3104 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2451310 (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-3104.json (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:6935 (opens in a new tab)