Description
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.
Published: 2026-06-16
Score: 5.9 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

A use‑after‑free occurs in Zephyr RTOS’s IPv6 MLD send routine. After a successful net_send_data(pkt) call the stack reads the packet’s interface owner from a freed packet. The subsequent use of that interface pointer by the statistics path can cause a null‑pointer dereference, a stale pointer write, or memory corruption, leading primarily to a crash of the networking subsystem.

Affected Systems

Devices that run Zephyr RTOS and include the sys‑net module subsys/net/ip/ipv6_mld.c without the fix introduced in commit 3159c53e8e7d233c2a85a0798cf25ac441db6dae are vulnerable. The flaw exists in all Zephyr releases prior to this patch and affects any deployment that relies on IPv6 MLD handling on a local link.

Risk and Exploitability

The CVSS score of 5.9 denotes moderate severity, while an EPSS score of less than 1% indicates a very low probability of exploitation in the wild. The vulnerability is triggerable remotely over the local link via an unauthenticated MLDv2 General Query and does not grant privilege escalation; it simply causes the networking stack to crash, resulting in a denial of service. The flaw is not listed in the CISA KEV catalog, and no public exploits are known.

Generated by OpenCVE AI on July 27, 2026 at 03:40 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Upgrade Zephyr to a version that incorporates commit 3159c53e8e7d233c2a85a0798cf25ac441db6dae or apply that patch directly to the source code.
  • If an immediate patch cannot be applied, disable the per‑interface statistics feature (CONFIG_NET_STATISTICS_PER_INTERFACE) until the fix is in place, as the bug is triggered only when that path is exercised.
  • Block unsolicited MLDv2 General Queries destined for link‑local addresses at the network boundary, or configure the device to ignore unknown MLD queries to prevent remote triggering.

Generated by OpenCVE AI on July 27, 2026 at 03:40 UTC.

Tracking

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Advisories

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History

Tue, 14 Jul 2026 19:00:00 +0000

Type Values Removed Values Added
Description 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. 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.
Title Use-after-free of net_pkt in IPv6 MLD send path triggerable by a link-local MLD Query Use-after-free of `net_pkt` in IPv6 MLD send path triggerable by a link-local MLD Query

Tue, 16 Jun 2026 17:45:00 +0000

Type Values Removed Values Added
First Time appeared Zephyrproject
Zephyrproject zephyr
Vendors & Products Zephyrproject
Zephyrproject zephyr

Tue, 16 Jun 2026 16:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Tue, 16 Jun 2026 15:00:00 +0000

Type Values Removed Values Added
Description 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.
Title Use-after-free of net_pkt in IPv6 MLD send path triggerable by a link-local MLD Query
Weaknesses CWE-416
References
Metrics cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H'}

Subscriptions

Zephyrproject Zephyr
cve-icon MITRE

Status: PUBLISHED

Assigner: zephyr

Published:

Updated: 2026-07-14T18:38:29.803Z

Reserved: 2026-06-02T15:10:54.577Z

Link: CVE-2026-10637

cve-icon Vulnrichment

Updated: 2026-06-16T15:30:17.187Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-06-16T15:16:33.987

Modified: 2026-06-16T15:23:42.240

Link: CVE-2026-10637

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-07-27T03:45:08Z

Weaknesses