Medium Memory corruption

CVE-2025-12899 — net: icmp: Out of bound memory read

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.

Published Jan 30, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: zephyr

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.3% (30-day exploitation probability)+4
Technical severity (medium)+3
Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.34%

ahead of 26% of scored CVEs · Oct 14, 2026

Affects

Zephyrproject-rtos

Zephyr

CVSS base

6.5

Medium · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

Yes

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Zephyrproject-rtos Zephyr).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Zephyrproject-rtos	Zephyr	< 3.7.2≥ 4.0.0 and < 4.2.2	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

None

User interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

Low

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
6.5	CVSS 3.1	Medium	3.9	2.5	vulnerabilities@zephyrproject.org via NIST National Vulnerability Database
6.5	CVSS 3.1	Medium	—	—	zephyr via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L (score shown at the top: vulnerabilities@zephyrproject.org)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-843 · Type Confusion

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.34%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.

web/proxy/WAF logsnetwork IDS/IPSendpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

2026
Affected products removed · 1
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Affected products added · zephyrproject-rtos/zephyr
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Affected products removed · 2
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Affected products added · zephyrproject-rtos/zephyr
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Affected products added · zephyrproject-rtos/zephyr
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
CVSS changed · 6.5
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Deferred
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
Jan 30, 2026 · zephyr

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

1 on the record

github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-c2vg-hj83-c2vg
NIST National Vulnerability Database

Elsewhere on this site

Zephyrproject-rtos
every CVE for this vendor

Memory corruption
same class

CWE-843
other pages naming this weakness

Related CVEs (same products)

High CVE-2026-13351 net: Maliciously fragmented IPv6 packets can prevent receiving/processing future incoming packets Jun 25, 2026
High CVE-2026-5068 bt: l2cap le coc: remote oob write via seg counter stored in net_buf user_data Jun 9, 2026
Critical CVE-2026-5067 Out-of-bounds read/write in HTTP WebSocket upgrade via non-null-terminated Sec-WebSocket-Key Jun 9, 2026
High CVE-2026-5066 net: sockets: tls: Potential out-of-bounds write/read in socket_op_vtable::connect function Jun 4, 2026
Medium CVE-2026-5589 Out-of-bounds write caused by an integer underflow in the Bluetooth Mesh subsystem. Jun 4, 2026
High CVE-2026-5071 can: Local Denial of Service via SocketCAN Send May 30, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No fixed version, patch or mitigation documented.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2025-12899 is "net: icmp: Out of bound memory read", rated Medium. It affects Zephyr (Zephyrproject-rtos); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.5 describes technical severity. EPSS 0.34% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

Comments

Moderated technical discussion. Read the community guidelines.

No comments yet.