CVE-2025-8677Network attack vector

Resource exhaustion via malformed DNSKEY handling

Published Oct 22, 2025 · Updated Nov 4, 2025

Denial of service in Internet Systems Consortium BIND 9 allows remote attackers to exhaust resolver CPU through crafted DNS queries. The validator in lib/dns/validator.c fails to count malformed DNSKEY records as validation failures, permitting repeated expensive validation work. The target must operate as a recursive resolver and query records in the crafted zone; authoritative-only service is believed unaffected, and the reported consequence is degraded or unavailable DNS resolution.

CVSS severity7.5
High
EPSS probability11.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Internet Systems Consortium BIND 9 allows remote attackers to exhaust resolver CPU through crafted DNS queries. The validator in lib/dns/validator.c fails to count malformed DNSKEY records as validation failures, permitting repeated expensive validation work. The target must operate as a recursive resolver and query records in the crafted zone; authoritative-only service is believed unaffected, and the reported consequence is degraded or unavailable DNS resolution.

The record

CVE
CVE-2025-8677
Published
Oct 22, 2025
Updated
Nov 4, 2025
Vendor
Internet Systems Consortium
Product
BIND 9
Classifications
CWE-405, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 22, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=9.18.0 <=9.18.39
  2. Affected versionversion=9.18.11-S1 <=9.18.39-S1
  3. Affected versionversion=9.20.0 <=9.20.13
  4. Affected versionversion=9.20.9-S1 <=9.20.13-S1
  5. Affected versionversion=9.21.0 <=9.21.12

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Internet Systems Consortium · BIND 9version=9.18.0 <=9.18.39; version=9.18.11-S1 <=9.18.39-S1; version=9.20.0 <=9.20.13; version=9.20.9-S1 <=9.20.13-S1; version=9.21.0 <=9.21.12

Published CVSS scores

7.5Internet Systems ConsortiumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-405Asymmetric Resource Consumption (Amplification)
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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