VulnerabilityPublished 28 Oct 2025Updated 9 Dec 2025

CVE-2025-11375: HashiCorp Consul · Unthrottled Resource Allocation

Affects HashiCorp ConsulSource CVE Database V5

Not known to be exploited · CVSS 6.5 Medium · fixed in 1.22.0 : update HashiCorp Consul when convenient.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

6.5Medium

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

EPSS: 0.4% chance of exploitation in 30 days – higher than 36% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 1.22.0, 1.21.6, 1.20.8 +1

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
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: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
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 28 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

Upgrade HashiCorp Consul to 1.22.0, 1.21.6, 1.20.8 or 1.18.12.

Affected software

Product	Affected	Fixed in
HashiCorp Consul	Affected <1.18.12 <1.20.8 <1.21.6 <1.22.0	Fixed in 1.18.12 1.20.8 1.21.6 1.22.0

AI-suggested

To mitigate CVE-2025-11375, European organizations should: 1) Immediately upgrade to the fixed versions of HashiCorp Consul Community Edition (1.22.0) or the corresponding Enterprise versions (1.22.0, 1.21.6, 1.20.8, 1.18.12). 2) Implement network-level protections such as rate limiting and request size restrictions on the event endpoint to prevent oversized requests from reaching Consul. 3) Monitor Consul logs and network traffic for anomalous large Content-Length headers or unusual request patterns indicative of exploitation attempts. 4) Employ Web Application Firewalls (WAFs) or API gateways capable of enforcing maximum request size limits and throttling. 5) Conduct regular vulnerability scanning and penetration testing focused on resource exhaustion vectors. 6) Isolate Consul instances within secure network segments and restrict access to trusted users and systems only, minimizing the attack surface. 7) Maintain an incident response plan that includes DoS scenarios affecting service discovery components. These steps go beyond generic patching by emphasizing proactive detection, network controls, and operational readiness.

Description

Consul and Consul Enterprise’s (“Consul”) event endpoint is vulnerable to denial of service (DoS) due to lack of maximum value on the Content Length header. This vulnerability, CVE-2025-11375, is fixed in Consul Community Edition 1.22.0 and Consul Enterprise 1.22.0, 1.21.6, 1.20.8 and 1.18.12.

Impact

For European organizations, the primary impact of CVE-2025-11375 is the potential for denial of service attacks against critical infrastructure components that rely on HashiCorp Consul for service discovery, configuration, and orchestration. Disruption of Consul services can cascade to affect microservices communication, load balancing, and automated infrastructure management, leading to downtime or degraded performance of business-critical applications. This is particularly significant for sectors with high cloud and DevOps adoption such as finance, telecommunications, and public services. Additionally, organizations using Consul in multi-tenant or shared environments may face increased risk if attackers can exploit the vulnerability to impact multiple customers. While no data breach or integrity compromise is indicated, availability loss can result in operational delays, financial losses, and reputational damage. The absence of known exploits in the wild reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits post-disclosure.

CWE-770Allocation of Resources Without Limits or Throttling (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #25
The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.
Requirements
Clearly specify the minimum and maximum expectations for capabilities, and dictate which behaviors are acceptable when resource allocation reaches limits.
Architecture and Design
Limit the amount of resources that are accessible to unprivileged users. Set per-user limits for resources. Allow the system administrator to define these limits. Be careful to avoid CWE-410.
Architecture and Design
Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended.
OWASP Cheat Sheets
Abuse Case (opens in a new tab)
OWASP ASVS 4.0.3
V8.1.4 (opens in a new tab)
V13.4.1 (opens in a new tab)
V11.1.4 (opens in a new tab)
Attack patterns
XML Ping of the Death (opens in a new tab)
Exponential Data Expansion (opens in a new tab)
Serialized Data Parameter Blowup (opens in a new tab)
Serialized Data with Nested Payloads (opens in a new tab)
Oversized Serialized Data Payloads (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

discuss.hashicorp.com/t/hcsec-2025-28-consuls-event-endpoint-is-vulnerable-to-denial-of-service/76723 (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 9 Dec 2025, 04:08 UTC

WeaknessesCWE-770

Technical details

References

Community reviews

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