CVE-2025-65493VulnerabilityPublished 24 Nov 2025

CVE-2025-65493: n/a

Source CVE Database V5

Not known to be exploited · CVSS 7.5 High.

Data as of 26 Oct 2026, 08:30 UTC

CVSS 3.1 base score

7.5High

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

EPSS: 0.4% chance of exploitation in 30 days – higher than 34% 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 24 Nov 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 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

To mitigate CVE-2025-65493, European organizations should first identify all systems and devices using libcoap version 4.3.5 or earlier. In the interim, developers and integrators should review and modify the src/coap_openssl.c code to add robust NULL checks after BIO_get_data() calls to prevent dereferencing NULL pointers. Network-level mitigations include deploying rate limiting and anomaly detection to identify and block suspicious DTLS/TLS connection attempts that could trigger the vulnerability. Segmentation of IoT and constrained device networks can limit exposure. Additionally, organizations should implement comprehensive monitoring to detect service crashes or unusual device behavior indicative of exploitation attempts. For critical environments, consider fallback or redundancy mechanisms to maintain availability during potential attacks. Engaging with device vendors to ensure timely firmware or software updates is also essential. Finally, applying defense-in-depth strategies such as secure coding reviews and fuzz testing for similar vulnerabilities in protocol implementations can reduce future risks.

Description

CVE-2025-65493 is a high-severity vulnerability in libcoap 4.3.5, specifically in the src/coap_openssl.c component. It involves a NULL pointer dereference triggered by crafted DTLS/TLS connections causing BIO_get_data() to return NULL, leading to a denial of service (DoS). This vulnerability can be exploited remotely without authentication or user interaction. While no known exploits are currently in the wild, the flaw allows attackers to crash affected services, impacting availability. European organizations using libcoap in IoT or constrained device environments may face service disruptions. Mitigation requires patching or applying workarounds to handle NULL pointers safely in the affected code. Countries with significant IoT deployments and critical infrastructure relying on constrained application protocols are most at risk.

Impact

For European organizations, the primary impact of CVE-2025-65493 is the potential for denial of service attacks against devices and services using libcoap 4.3.5 for DTLS/TLS-secured CoAP communications. This can affect IoT deployments, smart city infrastructure, industrial control systems, and other constrained environments where libcoap is integrated. Disruptions could lead to temporary loss of device availability, impacting operational continuity and potentially safety-critical functions. Given the increasing adoption of IoT and constrained protocols in sectors such as energy, transportation, healthcare, and manufacturing across Europe, the vulnerability could have widespread operational consequences. The lack of required authentication or user interaction lowers the barrier for attackers, increasing the risk of automated or large-scale DoS campaigns. Although confidentiality and integrity are not directly impacted, the availability degradation could indirectly affect business processes and critical infrastructure services. Organizations relying on libcoap in their network stacks or embedded devices should consider this vulnerability a significant risk to service reliability.

CWE-476NULL Pointer Dereference (opens in a new tab)
Base weaknessLikelihood of exploit: MediumCWE Top 25 (2025): #13OWASP Top 10 A10:2025: Mishandling of Exceptional Conditions (opens in a new tab)
The product dereferences a pointer that it expects to be valid but is NULL.
Implementation
For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished.
Requirements
Select a programming language that is not susceptible to these issues.
Implementation
Check the results of all functions that return a value and verify that the value is non-null before acting upon it.
OWASP Cheat Sheets
Logging (opens in a new tab)
Error Handling (opens in a new tab)
OWASP ASVS 4.0.3
V11.1.7 (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 1 Dec 2025, 14:41 UTC

WeaknessesCWE-476

Technical details

References

Community reviews

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