# CVE-2026-13481: Out-of-bounds read in PTP management TLV TIME parsing in Zephyr net PTP

Status: published. Published: 2026-08-26. Updated: 2026-11-04.

The IEEE 1588 PTP management-message parser in subsys/net/lib/ptp/tlv.c mishandles the PTP_MGMT_TIME management id. In tlv_mgmt_post_recv(), the PTP_MGMT_TIME case casts mgmt_tlv->data to a 10-byte struct ptp_timestamp and reads it (then byte-swaps and writes it back) without first checking that the TLV data field is at least sizeof(struct ptp_timestamp). Every sibling management id in the same switch validates its length first; PTP_MGMT_TIME was the only case lacking that check.

The length passed in is the management data size (tlv->length - 2), and the upstream guard in ptp_tlv_post_recv() only requires tlv->length > 2, while msg_tlv_post_recv() validates only that the TLV fits within the received byte count, not a per-id minimum. A peer on the local PTP segment can therefore send a PTP_MSG_MANAGEMENT message carrying a short PTP_MGMT_TIME TLV (data as small as 2 bytes), causing the parser to read and write 8 bytes beyond the validated data. The message type and TLV contents are taken straight off the wire, so the path is reachable by any adjacent attacker when CONFIG_PTP is enabled.

The over-read and write-back stay within the struct ptp_msg allocation (mgmt_tlv->data lives in the leading mtu[NET_ETH_MTU] union member, so data + 10 lands at most a few bytes past mtu[], inside the same object), so this is an out-of-bounds read of adjacent in-object memory plus a bounded in-place corruption of the message's parsed timestamp, not past-allocation memory corruption. Impact is limited to minor information exposure of adjacent bytes and corruption of the device's parsed management TIME value; there is no crash on the access and no reachable reference-count corruption.

The fix adds if (length < sizeof(struct ptp_timestamp)) { return -EBADMSG; } before the cast, matching the other management-id cases and fully closing the receive-path defect.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: zephyr) — https://github.com/zephyrproject-rtos/zephyr/commit/de98c3721a0e21ca269313997736f4f6193909ef
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: vulnerabilities@zephyrproject.org) — https://github.com/zephyrproject-rtos/zephyr/commit/de98c3721a0e21ca269313997736f4f6193909ef
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: vulnerabilities@zephyrproject.org) — https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-mh5r-jxh8-hxwx

## Affected products and versions

- zephyrproject / zephyr (zephyr): ≥ 3.7.0; < 4.3.2 (affected, semver); ≥ 4.4.0; < 4.4.2 (affected, semver). Source: CNA: zephyr

## NVD configuration conditions

Affected CPE matches depend on the following AND/OR and negation conditions:

```json
[
  {
    "negate": false,
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:o:zephyrproject:zephyr:*:*:*:*:*:*:*:*",
            "versionEndIncluding": "4.4.1",
            "versionStartIncluding": "3.7.0",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ],
    "operator": "OR"
  }
]
```

## Severity and prioritization

- CVSS 3.1: 5.4 (medium); CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N; source: CNA: zephyr

- CVSS 3.1: 5.4 (medium); CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N; source: NVD: vulnerabilities@zephyrproject.org

- CISA KEV: No listing in collected sources

- EPSS: 0.24% as of 2026-11-03; percentile 15.73%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-125

## Exploit evidence

- exploit: https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-mh5r-jxh8-hxwx (vulnerabilities@zephyrproject.org)

## References

- https://github.com/zephyrproject-rtos/zephyr/commit/de98c3721a0e21ca269313997736f4f6193909ef (CNA: zephyr; patch)

- https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-mh5r-jxh8-hxwx (CNA: zephyr)

- https://github.com/zephyrproject-rtos/zephyr/commit/de98c3721a0e21ca269313997736f4f6193909ef (vulnerabilities@zephyrproject.org; Patch)

- https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-mh5r-jxh8-hxwx (vulnerabilities@zephyrproject.org; Exploit, Patch, Vendor Advisory)

## Provenance

- CNA: zephyr: https://www.cve.org/CVERecord?id=CVE-2026-13481; retrieved 2026-11-04; source updated 2026-11-04

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-13481; retrieved 2026-11-04; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-13481; retrieved 2026-11-04; source updated Not reported

Revision: b5efe84a10c82c368bca0d87ba6dd65b79265e48d86af55b92b3e07048c734d1

Canonical: https://y2.dev/cve/CVE-2026-13481

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