CVE-2026-10637 — Use-after-free of `net_pkt` in IPv6 MLD send path triggerable by a link-local MLD Query
subsys/net/ip/ipv6_mld.c:mld_send() read the packet interface via net_pkt_iface(pkt) after net_send_data(pkt) returned successfully. Per the network stack's ownership contract (include/zephyr/net/net_core.h, and the explicit warning in subsys/net/ip/net_core.c:453-460 'do not use pkt after that call'), a successful send transfers ownership of the net_pkt and the L2 driver frees it (e.g. ethernet_send() unrefs the packet on success, subsys/net/l2/ethernet/ethernet.c:790), returning it to its k_mem_slab. The subsequent net_pkt_iface(pkt) is therefore a read of a freed object; the recovered interface pointer is then dereferenced and incremented by the per-interface statistics path (net_stats.h UPDATE_STAT/SET_STAT) when CONFIG_NET_STATISTICS_PER_INTERFACE is enabled. If the freed slot is concurrently reallocated, pkt->iface may read back as NULL (NULL-pointer dereference / crash) or as a stale/garbage pointer (stray increment write / memory corruption). The path is reachable remotely on the local link without authentication: handle_mld_query() (registered for NET_ICMPV6_MLD_QUERY) responds to a valid MLDv2 General Query (unspecified multicast address, hop limit 1) by calling send_mld_report() -> mld_send(). The result is a remotely triggerable denial of service of the networking stack, with a narrow possibility of memory corruption. The fix caches the interface in a local before sending and no longer touches the packet after net_send_data(). The IPv4/IGMP sibling (igmp_send) already used the corrected pattern.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.3% (30-day exploitation probability)+3
- Technical severity (high)+6
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.
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.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented patch — github.com (NIST National Vulnerability Database)
- Documented patch — github.com (NIST National Vulnerability Database)
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 Zephyr).
- Apply the fixed version or the patch documented under Remediation.
- 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 | Zephyr | ≥ 1.12.0 and < 4.5.0 | Vulnerable | NIST National Vulnerability Database |
| Zephyrproject | Zephyr | ≥ 1.12.0 and < 4.3.1≥ 4.4.0 and < 4.4.1 | Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
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 |
|---|---|---|---|---|---|
| 7.1 | CVSS 3.1 | High | 2.8 | 4.2 | nvd@nist.gov via NIST National Vulnerability Database |
| 5.9 | CVSS 3.1 | Medium | 1.6 | 4.2 | vulnerabilities@zephyrproject.org via NIST National Vulnerability Database |
| 5.9 | CVSS 3.1 | Medium | — | — | zephyr via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H (score shown at the top: nvd@nist.gov) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
EPSS over time FIRST
Oct 13, 2026 → Oct 15, 2026 · 3 reading(s) · max 0.30%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products removed · 1
- Affected products added · zephyrproject/zephyr
- Affected products added · zephyrproject/zephyr
- SSVC assessment updated
- Record published
- Fix documented
- CVSS changed · 7.1
- Source status changed · → Modified
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 13, 2026 – Oct 13, 2026
References
2 on the record
Elsewhere on this site
Related CVEs (same products)
- Medium CVE-2026-75084 Out-of-bounds write in the TI CC1200 IEEE 802.15.4 driver from an unvalidated radio-supplied packet length 1d
- Medium CVE-2026-75085 Out-of-bounds read from received-frame length underflow in the STM32WBA IEEE 802.15.4 driver 1d
- Medium CVE-2026-75083 Integer underflow of the radio-reported frame length causes an out-of-bounds write in the NXP KW41Z IEEE 802.15.4 driver 1d
- High CVE-2026-19673 Out-of-bounds read and net_buf length underflow in Zephyr Ethernet L2 when parsing a truncated VLAN header 1d
- Medium CVE-2026-19940 Bluetooth HFP AG reuses a connection slot while a delayable work item is still armed, corrupting kernel timeout bookkeeping 2d
- Medium CVE-2026-19939 Bluetooth Classic AVDTP: stale timeout work on signalling-channel disconnect leads to kernel timeout-list corruption 2d
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 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-2026-10637 is "Use-after-free of `net_pkt` in IPv6 MLD send path triggerable by a link-local MLD Query", rated High. It affects Zephyr (Zephyrproject); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.1 describes technical severity. EPSS 0.30% 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.
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