VulnerabilityPublished 24 Oct 2025

CVE-2025-61430: Simple DNS Plus · Reliance on Reverse DNS Resolution for a Security-Critical Action

Source CVE Database V5

Not known to be exploited · CVSS 6.5 Medium.

Data as of 26 Oct 2026, 15:59 UTC

CVSS 3.1 base score

6.5Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 17% 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:L/I:L/A:N

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

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: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 24 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

AI-suggested

European organizations should implement several targeted mitigations beyond generic advice: 1) Restrict DNS over TCP query access to trusted clients and networks using firewall rules and access control lists to minimize exposure. 2) Monitor DNS server logs and network traffic for anomalies indicative of malformed TCP length prefixes or unusual query patterns that may signal exploitation attempts. 3) Employ network segmentation to isolate DNS servers from untrusted networks and reduce the attack surface. 4) Use DNS encryption technologies such as DNS over HTTPS (DoH) or DNS over TLS (DoT) where possible to protect query confidentiality and integrity. 5) Engage with the Simple DNS Plus vendor to obtain timely patches or workarounds once available and prioritize their deployment. 6) Conduct regular security assessments and penetration testing focusing on DNS infrastructure to detect similar concurrency or buffering issues. 7) Educate network administrators about this vulnerability to ensure prompt detection and response.

Description

Improper handling of DNS over TCP in Simple DNS Plus v9 allows a remote attacker with querying access to the DNS server to cause the server to return request payloads from other clients. This happens when the TCP length prefix is malformed (len differs from actual packet len), and due to a concurrency/buffering issue, even when the lengths match. A length prefix that is smaller than the actual packet size increases information leakage. In summary, this vulnerability allows an attacker to see DNS queries of other clients.

Impact

For European organizations, this vulnerability poses a significant privacy risk as DNS queries often reveal sensitive information about internal network activities, user behavior, and accessed resources. Leakage of DNS queries could facilitate further reconnaissance by attackers, enabling targeted phishing, malware distribution, or lateral movement within networks. Organizations in sectors such as finance, healthcare, government, and critical infrastructure are particularly vulnerable due to the sensitivity of their DNS traffic. The integrity impact, while limited, could allow attackers to infer or manipulate query responses indirectly by observing query patterns. Although availability is not affected, the confidentiality breach could lead to regulatory compliance issues under GDPR and other data protection laws, potentially resulting in legal and financial penalties. The medium severity rating reflects that while the vulnerability is not immediately catastrophic, it undermines trust in DNS infrastructure and could be leveraged as part of a broader attack chain.

CWE-350Reliance on Reverse DNS Resolution for a Security-Critical Action (opens in a new tab)
Variant weaknessOWASP Top 10 A07:2025: Authentication Failures (opens in a new tab)
The product performs reverse DNS resolution on an IP address to obtain the hostname and make a security decision, but it does not properly ensure that the IP address is truly associated with the hostname.
Architecture and Design
Use other means of identity verification that cannot be simply spoofed. Possibilities include a username/password or certificate.
Implementation
Perform proper forward and reverse DNS lookups to detect DNS spoofing.
OWASP Cheat Sheets
Docker Security (opens in a new tab)
OWASP Authentication (opens in a new tab)
OWASP ASVS 4.0.3
V10.3.3 (opens in a new tab)
V2.8.5 (opens in a new tab)
V2.8.4 (opens in a new tab)
Attack patterns
DNS Cache Poisoning (opens in a new tab)
DNS Rebinding (opens in a new tab)
User-Controlled Filename (opens in a new tab)
Pharming (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 31 Oct 2025, 15:05 UTC

WeaknessesCWE-350

Technical details

References

Community reviews

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