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

> An adjacent attacker can trigger an out-of-bounds read and minor memory corruption in the Zephyr PTP parser, exposing adjacent memory bytes.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 26 Aug 2026
- **Updated:** 31 Aug 2026
- **Also known as:** GHSA-mh5r-jxh8-hxwx

## What is CVE-2026-13481?

CVE-2026-13481 is a medium-severity vulnerability in Zephyrproject Zephyr, published on 26 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-13481?

It affects 1 product.


Products: Zephyrproject Zephyr.

## How do I fix CVE-2026-13481?

No fix has been published for CVE-2026-13481 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-13481 being exploited?

There is no known exploitation of CVE-2026-13481 in the wild and no public exploit code.

## Other vulnerabilities in Zephyrproject Zephyr

- [CVE-2026-5067](https://insights.sbomify.com/CVE-2026-5067/): Out-of-bounds read/write in HTTP WebSocket upgrade via non-null-terminated Sec-WebSocket-Key (critical 9.8)
- [CVE-2022-3806](https://insights.sbomify.com/CVE-2022-3806/): Bluetooth HCI Error Handling Double Free (critical 9.8)
- [CVE-2017-14199](https://insights.sbomify.com/CVE-2017-14199/): Memory corruption in getaddrinfo (critical 9.8)
- [CVE-2018-1000800](https://insights.sbomify.com/CVE-2018-1000800/): Null dereference in n/a (critical 9.8)
- [CVE-2021-3329](https://insights.sbomify.com/CVE-2021-3329/): DOS: Incorrect handling of the initial HCI ACL_MTU handshake packet leads to crash of bluetooth host layer (critical 9.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-13481 and fix it if it is affected.

What it is: CVE-2026-13481 is a medium-severity vulnerability in Zephyrproject Zephyr, published on 26 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-13481 in the wild and no public exploit code.

Affected product: Zephyrproject Zephyr. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-13481/ (Markdown: https://insights.sbomify.com/CVE-2026-13481/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-13481
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-13481
- OSV: https://osv.dev/vulnerability/CVE-2026-13481

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-13481/
Summaries are generated and may contain mistakes; the official description above is the record.