VulnerabilityPublished 7 Oct 2025Updated 3 Nov 2025

CVE-2025-53476: OpenPLC_v3 · Missing Release of File Descriptor or Handle after Effective Lifetime

Affects OpenPLC_v3Source CVE Database V5

Not known to be exploited · CVSS 5.3 Medium.

Data as of 26 Oct 2026, 17:16 UTC

CVSS 3.1 base score

5.3Medium

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

EPSS: 0.4% chance of exploitation in 30 days – higher than 39% 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:L

Attack Vector: Network
Attack Complexity: Low
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: 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: 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 7 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

Network Segmentation: Isolate industrial control networks running OpenPLC from general IT networks and the internet to reduce exposure.
Connection Limits: Implement firewall or network device rules to limit the number of concurrent TCP connections to the ModbusTCP server, preventing resource exhaustion.
Monitoring and Alerting: Deploy network monitoring to detect unusual spikes in TCP connection attempts targeting ModbusTCP ports, enabling early detection of exploitation attempts.
Resource Hardening: Configure operating system limits on file descriptors and handles to prevent exhaustion and enable graceful degradation.
Vendor Patching: Monitor OpenPLC project updates and apply patches or updated versions addressing this vulnerability as soon as they become available.
Access Controls: Restrict access to ModbusTCP services to trusted hosts and networks only, using VPNs or secure tunnels where possible.
Incident Response Preparation: Develop and test response plans for industrial control system denial of service scenarios to minimize downtime impact.

Description

A denial of service vulnerability exists in the ModbusTCP server functionality of OpenPLC _v3 a931181e8b81e36fadf7b74d5cba99b73c3f6d58. A specially crafted series of network connections can lead to the server not processing subsequent Modbus requests. An attacker can open a series of TCP connections to trigger this vulnerability.

Impact

For European organizations, especially those operating in industrial automation, manufacturing, energy, and critical infrastructure sectors, this vulnerability poses a risk of operational disruption. OpenPLC is used in programmable logic controllers that manage industrial processes; a denial of service in the ModbusTCP server can halt command processing, potentially causing production downtime, safety incidents, or cascading failures in automated systems. The impact is primarily on availability, which can translate into financial losses, regulatory non-compliance, and reputational damage. Given the reliance on industrial control systems in Europe’s manufacturing hubs (e.g., Germany, France, Italy) and energy sectors, the vulnerability could affect essential services and supply chains. Although no known exploits exist yet, the ease of exploitation (no authentication or user interaction required) means attackers could weaponize this vulnerability if they gain network access. Organizations with exposed or poorly segmented industrial networks are at higher risk.

CWE-775Missing Release of File Descriptor or Handle after Effective Lifetime (opens in a new tab)
Variant weakness
The product does not release a file descriptor or handle after its effective lifetime has ended, i.e., after the file descriptor/handle is no longer needed.
Operation · Architecture and Design · Resource Limitation
Use resource-limiting settings provided by the operating system or environment. For example, when managing system resources in POSIX, setrlimit() can be used to set limits for certain types of resources, and getrlimit() can determine how many resources are available.
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Description

AI analysisMachine-generated, updated 3 Nov 2025, 18:12 UTC

WeaknessesCWE-775

Technical details

References

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