CVE-2026-81563
HIGHDescription
A BIND resolver encountering an SVCB/HTTPS AliasMode record referencing 14 or more SVCB/HTTPS ServiceMode records may fail to properly deallocate internal resources. If this happens repeatedly, resource exhaustion will eventually prevent the resolver from performing new recursive lookups. This issue affects BIND 9 versions 9.18.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.18.11-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1.
How to fix
No published remediation has been found for this vulnerability's affected products yet.
Mitigation guidance may be in the linked vendor advisories in the References section below.
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CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Exploit Intelligence
EPSS data unavailable for this CVE.
References
Related Vulnerabilities
Other CWE-401 (Missing Release of Memory (Memory Leak)) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2020-13934 | High | 7.5 | 64% | - | Fix |
| CVE-2016-6304 | High | 7.5 | 63% | - | Fix |
| CVE-2019-12265 | Medium | 5.3 | 60% | - | Fix |
| CVE-2001-0136 | Medium | 5.0 | 45% | - | - |
| CVE-2016-4232 | High | 7.5 | 36% | - | - |
| CVE-2001-0543 | Medium | 5.0 | 19% | - | - |
Common questions
How do I fix CVE-2026-81563?
No published fix for CVE-2026-81563 has been found yet. Check the linked vendor advisories for guidance as it becomes available.
How severe is CVE-2026-81563?
CVE-2026-81563 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-09-17.