CVE-2025-30187VulnerabilityPublished 18 Sep 2025Updated 4 Nov 2025

CVE-2025-30187: PowerDNS DNSdist · Infinite Loop

Affects PowerDNS DNSdistSource CVE Database V5

Not known to be exploited · CVSS 3.7 Low.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

3.7Low

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 21% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

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

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: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
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: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Sep 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 2026-10-26.

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 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
PowerDNS DNSdist	Affected =1.9.0 =2.0.0	Fixed in–

AI-suggested

To mitigate CVE-2025-30187, European organizations should prioritize the following actions: 1) Monitor PowerDNS announcements and apply official patches or updates for DNSdist as soon as they are released to address this vulnerability. 2) If immediate patching is not feasible, consider disabling DNS over HTTPS (DoH) processing via the nghttp2 library in DNSdist configurations to prevent triggering the infinite loop. 3) Implement network-level protections such as rate limiting and filtering to restrict suspicious or malformed DoH traffic that could exploit this vulnerability. 4) Deploy robust monitoring of DNSdist CPU usage and query patterns to detect abnormal resource consumption indicative of an attack. 5) Use redundant DNS infrastructure and load balancing to minimize the impact of any single server being affected by a DoS condition. 6) Conduct regular security assessments and penetration testing focusing on DNS services to identify and remediate similar issues proactively. 7) Engage with vendors and security communities to stay informed about emerging threats related to DNSdist and DoH implementations.

Description

In some circumstances, when DNSdist is configured to use the nghttp2 library to process incoming DNS over HTTPS queries, an attacker might be able to cause a denial of service by crafting a DoH exchange that triggers an unbounded I/O read loop, causing an unexpected consumption of CPU resources.

Impact

For European organizations, the primary impact of CVE-2025-30187 is the potential disruption of DNS services due to denial of service caused by excessive CPU consumption on DNSdist servers handling DoH queries. This can lead to degraded network performance, increased latency, or complete unavailability of DNS resolution, affecting internal and external communications. Organizations relying on DNSdist for critical DNS infrastructure, especially those supporting DoH to enhance privacy and security, may experience service interruptions impacting business operations, customer access, and online services. While the vulnerability does not expose sensitive data or allow unauthorized changes, the availability impact can indirectly affect confidentiality and integrity by disrupting security monitoring and response capabilities. The low CVSS score reflects limited direct damage, but in high-demand environments or where DNSdist is a single point of failure, the operational impact could be significant. European sectors such as telecommunications, finance, and government, which depend heavily on reliable DNS infrastructure, could be particularly sensitive to such disruptions.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 4 Nov 2025, 21:46 UTC

WeaknessesCWE-835

Technical details

References

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