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VulnerabilityPublished Updated

CVE-2026-19667: ISC BIND 9 · Numeric Truncation Error

Affects ISC BIND 9Source CVE Database V5

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Not known to be exploited · CVSS 7.5 High.

Data as of 30 Oct 2026, 20:25 UTC

CVSS 3.1 base score
7.5High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 47% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 16 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

Affected software

ProductAffectedFixed in
ISCBIND 9Affected
  • >=9.11.0 <=9.18.50
  • >=9.20.0 <=9.20.27
  • >=9.21.0 <=9.21.25
  • >=9.11.3-S1 <=9.18.50-S1
  • >=9.20.9-S1 <=9.20.27-S1
Fixed in–
GitHubisc/bind9pkg:github/isc/bind9Other threatsAffected
  • >=9.11.0 <=9.18.50
  • >=9.20.0 <=9.20.27
  • >=9.21.0 <=9.21.25
  • >=9.11.3-S1 <=9.18.50-S1
  • >=9.20.9-S1 <=9.20.27-S1
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Until a fix is confirmed, consider restricting or monitoring DNS responses from authoritative servers to mitigate potential exploitation.

Description

CVE-2026-19667 is a numeric truncation error vulnerability in ISC BIND 9's named DNS service. An attacker-controlled authoritative DNS server can send a crafted negative response of exactly 65536 bytes, causing named to create a zero-byte negative cache entry. Subsequent accesses to this cache entry cause the named service to abort, resulting in a denial of service. This affects multiple BIND 9 versions including 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, and their S1 variants.

References

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