VulnerabilityPublished 29 Sep 2025Updated 28 Oct 2025

CVE-2025-56233: Uncontrolled Resource Consumption

Source CVE Database V5

Not known to be exploited · CVSS 7.5 High.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 3.1 base score

7.5High

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 26% 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 29 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 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

Implement network-level filtering to detect and block anomalous TCP RST and SYN packets with suspicious sequence numbers, using intrusion detection/prevention systems (IDS/IPS) capable of deep packet inspection.
Deploy rate limiting on incoming TCP RST and SYN packets to reduce the impact of flooding attacks targeting the vulnerability.
Monitor network traffic for unusual patterns of TCP resets or connection interruptions indicative of exploitation attempts.
Isolate or segment systems running Openindiana to limit exposure to untrusted networks and reduce attack surface.
Engage with Openindiana maintainers or community to track patch releases and apply updates promptly once available.
Consider deploying alternative or updated TCP/IP stack implementations if feasible to mitigate the vulnerability.
Conduct regular incident response drills simulating denial of service scenarios to improve readiness.
Document and enforce strict network access controls and firewall rules to restrict unnecessary inbound TCP traffic to vulnerable systems.
Collaborate with upstream ISPs and network providers to implement upstream filtering or blackholing of attack traffic if under active exploitation. These targeted measures go beyond generic advice by focusing on TCP sequence number anomaly detection and network segmentation specific to this vulnerability.

Description

Openindiana, kernel SunOS 5.11 has a denial of service vulnerability. For the processing of TCP packets with RST or SYN flag set, Openindiana has a wide acceptable range of sequence numbers. It does not require the sequence number to exactly match the next expected sequence value, just to be within the current receive window, which violates RFC5961. This flaw allows attackers to send multiple random TCP RST/SYN packets to hit the acceptable range of sequence numbers, thereby interrupting normal connections and causing a denial of service attack.

Impact

For European organizations, this vulnerability can cause significant disruption to network services relying on Openindiana or SunOS 5.11 kernels. Denial of service attacks exploiting this flaw can interrupt critical TCP connections, impacting availability of applications, services, and infrastructure components. Organizations in sectors such as telecommunications, finance, government, and energy that may use Openindiana in legacy or specialized environments could face outages or degraded service quality. The attack can be launched remotely without authentication, increasing the risk of widespread disruption. Additionally, the denial of service could be leveraged as part of multi-stage attacks to distract or degrade defenses. The lack of patches means organizations must rely on network-level controls and monitoring to mitigate risk, which may be challenging in complex or high-throughput environments. Overall, the vulnerability threatens operational continuity and could lead to financial losses, reputational damage, and regulatory scrutiny under European data protection and operational resilience frameworks.

CWE-400Uncontrolled Resource Consumption (opens in a new tab)
Class weaknessLikelihood of exploit: High
The product does not properly control the allocation and maintenance of a limited resource.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
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. A strong authentication and access control model will help prevent such attacks from occurring in the first place.
Architecture and Design
Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or; uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed.
Architecture and Design
Ensure that protocols have specific limits of scale placed on them.
OWASP Cheat Sheets
File Upload (opens in a new tab)
OWASP ASVS 4.0.3
V12.1.1 (opens in a new tab)
Attack patterns
XML Ping of the Death (opens in a new tab)
Regular Expression Exponential Blowup (opens in a new tab)
Sustained Client Engagement (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

github.com/zq-star/TCP-Vuln-Report/blob/master/Openindiana%20minimal/tcp-rst-syn/openindiana-minimal-tcp-rst-syn.md (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 28 Oct 2025, 20:43 UTC

WeaknessesCWE-400

Technical details

References

Community reviews

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