VulnerabilityPublished 30 Jan 2026Updated 13 Oct 2026

CVE-2025-12899: zephyrproject-rtos Zephyr · Type Confusion

Affects zephyrproject-rtos ZephyrSource CVE Database V5

Not known to be exploited · CVSS 6.5 Medium : upgrade to 4.2.2 or 3.7.2 when convenient.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 3.1 base score

6.5Medium

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

EPSS: 0.3% chance of exploitation in 30 days – higher than 27% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 4.2.2, 3.7.2

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: Low
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: 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: 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 30 Jan 2026
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.

cwe-843

What to do

Upgrade zephyrproject-rtos Zephyr to 4.2.2 or 3.7.2.

Affected software

Product	Affected	Fixed in
zephyrproject-rtosZephyr	Affected >=4.0.0 <4.2.2	Fixed in 4.2.2
zephyrproject-rtosZephyr	Affected <3.7.2	Fixed in 3.7.2
GitHubzephyrproject-rtos/zephyr`pkg:github/zephyrproject-rtos/zephyr`Other threats	Affected *	Fixed in–
GitHubZephyr`pkg:github/Zephyr`Other threats	Affected <3.7.2 >=4.0.0 <4.2.2	Fixed in 3.7.2 4.2.2

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Monitor Zephyr project communications and apply official patches promptly once released to address CVE-2025-12899.
Implement network-level filtering to block or scrutinize ICMP packets with unusual or unexpected types, particularly ICMP type 128 in IPv4 traffic.
Employ intrusion detection/prevention systems (IDS/IPS) configured to detect anomalous ICMP traffic patterns indicative of exploitation attempts.
Segment networks to isolate IoT and embedded devices running Zephyr from critical infrastructure and sensitive data environments.
Conduct regular firmware audits and updates for devices using Zephyr to ensure they are not running vulnerable versions.
Use secure boot and runtime integrity checks to detect and prevent unauthorized modifications or exploitation attempts.
Engage in threat hunting activities focused on network traffic anomalies related to ICMP packets to identify early exploitation signs.
Collaborate with device vendors and suppliers to confirm patch availability and deployment status for affected devices.

Description

A flaw in Zephyr’s network stack allows an IPv4 packet containing ICMP type 128 to be misclassified as an ICMPv6 Echo Request. This results in an out-of-bounds memory read and creates a potential information-leak vulnerability in the networking subsystem.

Impact

For European organizations, the vulnerability presents a risk of information leakage and potential denial-of-service in devices running Zephyr RTOS, commonly found in IoT and embedded systems. Confidentiality could be compromised if attackers exploit the out-of-bounds read to extract sensitive data from device memory. Availability may also be impacted if the memory error leads to crashes or instability, disrupting critical services. This is particularly concerning for sectors such as industrial automation, smart infrastructure, healthcare devices, and automotive systems where Zephyr is deployed. The remote, unauthenticated nature of the exploit increases the threat surface, especially for devices exposed to untrusted networks or the internet. Organizations may face operational disruptions, data exposure, and increased risk of lateral movement within networks. The lack of known exploits currently provides a window for proactive mitigation, but the potential for future exploitation necessitates urgent attention.

References

github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-c2vg-hj83-c2vg (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 6 Feb 2026, 08:48 UTC

Technical details

References

Community reviews

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