VulnerabilityPublished 22 Oct 2025Updated 4 Nov 2025

CVE-2025-8677: ISC BIND 9 · Asymmetric Resource Consumption

Affects ISC BIND 9Source CVE Database V5

Not known to be exploited · 10% EPSS · CVSS 7.5 High.

Data as of 26 Oct 2026, 15:59 UTC

CVSS 3.1 base score

7.5High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 10.7% chance of exploitation in 30 days – higher than 95% 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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 22 Oct 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
ISC BIND 9	Affected 9.18.0 – 9.21.0 5 affected builds	Fixed in–

AI-suggested

Monitor ISC and trusted security advisories closely for official patches addressing CVE-2025-8677 and apply them promptly once released.
Until patches are available, implement rate limiting and query filtering on DNS servers to restrict queries for DNSKEY records or from suspicious sources to reduce exposure to malformed queries.
Deploy network-level protections such as firewalls and intrusion prevention systems (IPS) to detect and block anomalous DNS traffic patterns indicative of exploitation attempts.
Consider isolating DNS servers from direct internet exposure where possible, using DNS forwarders or recursive resolvers behind protective layers.
Review DNSSEC configurations and zone data for correctness to minimize the risk of malformed records triggering the vulnerability internally.
Conduct regular performance monitoring and alerting on DNS server CPU usage to detect early signs of exploitation or resource exhaustion.
Engage with DNS infrastructure providers and peers to share threat intelligence and coordinate defensive measures.
Prepare incident response plans specifically for DNS service disruptions to ensure rapid recovery and communication in case of an attack.

Description

Querying for records within a specially crafted zone containing certain malformed DNSKEY records can lead to CPU exhaustion. This issue affects BIND 9 versions 9.18.0 through 9.18.39, 9.20.0 through 9.20.13, 9.21.0 through 9.21.12, 9.18.11-S1 through 9.18.39-S1, and 9.20.9-S1 through 9.20.13-S1.

Impact

For European organizations, the impact of CVE-2025-8677 can be significant due to the critical role DNS servers play in network operations and internet connectivity. Organizations using vulnerable versions of ISC BIND 9 as authoritative or recursive DNS servers may experience denial-of-service conditions, resulting in service outages or degraded network performance. This can affect internal applications, external-facing services, and overall business continuity. The disruption of DNS services can also impact email delivery, web services, and other critical infrastructure dependent on DNS resolution. Given the vulnerability requires no authentication and no user interaction, attackers can remotely launch DoS attacks from anywhere on the internet. This risk is heightened for organizations with publicly accessible DNS servers or those that accept queries from untrusted networks. The potential for widespread disruption is notable in sectors such as finance, telecommunications, government, and critical infrastructure providers across Europe. Additionally, DNS infrastructure providers and ISPs in Europe could be targeted to cause broader regional impact. The lack of known exploits in the wild currently provides a window for mitigation, but the vulnerability's nature demands urgent remediation to prevent future exploitation.

CWE-405Asymmetric Resource Consumption (Amplification) (opens in a new tab)
Class weakness
The product does not properly control situations in which an adversary can cause the product to consume or produce excessive resources without requiring the adversary to invest equivalent work or otherwise prove authorization, i.e., the adversary's influence is "asymmetric."
Architecture and Design
An application must make resources available to a client commensurate with the client's access level.
Architecture and Design
An application must, at all times, keep track of allocated resources and meter their usage appropriately.
System Configuration
Consider disabling resource-intensive algorithms on the server side, such as Diffie-Hellman key exchange.
OWASP Cheat Sheets
File Upload (opens in a new tab)
OWASP ASVS 4.0.3
V12.1.1 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Nov 2025, 22:46 UTC

WeaknessesCWE-405

Technical details

References

Community reviews

Related threats