CVE-2026-15893

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Source

https://cve.org/CVERecord?id=CVE-2026-15893

Import Source

https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-15893.json

JSON Data

https://api.osv.dev/v1/vulns/CVE-2026-15893

Aliases

GHSA-8v32-9xf8-r765

Published

2026-09-14T18:49:55Z

Modified

2026-09-16T08:29:35Z

Severity

6.5 (Medium) CVSS_V3 - CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS Calculator

Summary

Zephyr IPv6 Neighbor Discovery zero reachable time from crafted Router Advertisement causes assertion/DoS

Details

net_if_ipv6_calc_reachable_time() in subsys/net/ip/net_if.c derives a randomized ND reachable time from ipv6->base_reachable_time as min_reachable + sys_rand32_get() % (max_reachable - min_reachable), where min_reachable = base/2 and max_reachable = 3*base/2 using integer division. When base_reachable_time is 1, both min_reachable and the modulus collapse so the function returns 0, and net_if_ipv6_set_reachable_time() stores that 0 into ipv6->reachable_time.

The base_reachable_time is attacker-controlled: handle_ra_input() in subsys/net/ip/ipv6_nbr.c accepts the Reachable Time field of an incoming Router Advertisement whenever it is nonzero and <= MAX_REACHABLE_TIME, so a single unauthenticated, link-local RA carrying a Reachable Time of 1 drives the computed reachable time to 0. Router Advertisements are unauthenticated by default and require only adjacency to the target link.

When a neighbor is subsequently confirmed reachable, net_ipv6_nbr_set_reachable_timer() reads the value and executes NET_ASSERT(time, "Zero reachable timeout!"). On builds with CONFIG_ASSERT enabled this triggers a fatal kernel assertion — a remote denial of service; on builds without assertions the reachable timer is armed with K_MSEC(0) and fires immediately, forcing reachable neighbors into perpetual re-solicitation (STALE), degrading Neighbor Discovery. The impact is limited to availability; there is no memory-safety, confidentiality, or integrity consequence.

Database specific

{
    "cna_assigner": "zephyr",
    "cwe_ids": [
        "CWE-617"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/15xxx/CVE-2026-15893.json"
}

References

Affected packages

Git / github.com/zephyrproject-rtos/zephyr

Affected ranges

Type

GIT

Repo

https://github.com/zephyrproject-rtos/zephyr

Events

Introduced

bdc3107d5c47d9cf4b6a4e948186a0a2730d92c5

Fixed

251079ed50464aa0976eb0738a5afbe009cc9d60

Database specific

Show details

{
    "extracted_events": [
        {
            "introduced": "1.7.0"
        },
        {
            "fixed": "4.4.2"
        }
    ],
    "source": [
        "AFFECTED_FIELD",
        "REFERENCES"
    ]
}

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-15893.json"

vanir_signatures

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        "deprecated": false,
        "digest": {
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            "length": 319
        },
        "id": "CVE-2026-15893-1f577ae1",
        "signature_type": "Function",
        "signature_version": "v1",
        "source": "https://github.com/zephyrproject-rtos/zephyr/commit/251079ed50464aa0976eb0738a5afbe009cc9d60",
        "target": {
            "file": "subsys/net/ip/net_if.c",
            "function": "net_if_ipv6_calc_reachable_time"
        }
    },
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        "deprecated": false,
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            ],
            "threshold": 0.9
        },
        "id": "CVE-2026-15893-97178f54",
        "signature_type": "Line",
        "signature_version": "v1",
        "source": "https://github.com/zephyrproject-rtos/zephyr/commit/251079ed50464aa0976eb0738a5afbe009cc9d60",
        "target": {
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]

vanir_signatures_modified

"2026-09-16T08:29:35Z"