# CVE-2026-41475: BACnet Stack: Out-of-Bounds Read in WritePropertyMultiple Decoder via Deprecated Tag Parser

> Unauthenticated remote attackers can read memory or crash embedded BACnet devices via a truncated WritePropertyMultiple request in the BACnet Stack library.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 24 Apr 2026
- **Updated:** 27 Apr 2026
- **Also known as:** GHSA-cvv4-v3g6-4jmv

## What is CVE-2026-41475?

CVE-2026-41475 is a high-severity vulnerability in bacnet-stack, published on 24 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to 1.4.3, an out-of-bounds read vulnerability in bacnet-stack's WritePropertyMultiple service decoder allows unauthenticated remote attackers to read past allocated buffer boundaries by sending a truncated WPM request. The vulnerability stems from wpm_decode_object_property() calling the deprecated decode_tag_number_and_value() function, which performs no bounds checking on the input buffer. A crafted BACnet/IP packet with a truncated property payload causes the decoder to read 1-7 bytes past the end of the buffer, leading to crashes or information disclosure on embedded BACnet devices. This vulnerability is fixed in 1.4.3.

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

## Which versions are affected by CVE-2026-41475?

It affects 1 product.


Products: Bacnetstack Bacnet Stack.

## How do I fix CVE-2026-41475?

No fix has been published for CVE-2026-41475 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-41475 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-41475 exists.

## Other vulnerabilities in bacnet-stack

- [CVE-2023-51773](https://insights.sbomify.com/CVE-2023-51773/): Memory corruption in n/a (critical 9.1)
- [CVE-2026-41502](https://insights.sbomify.com/CVE-2026-41502/): BACnet Stack: Off-by-One Out-of-Bounds Read in ReadPropertyMultiple Object ID Decoder (high 8.7)
- [CVE-2026-41503](https://insights.sbomify.com/CVE-2026-41503/): BACnet Stack: Out-of-Bounds Read in ReadPropertyMultiple Property Decoder via Deprecated Tag Parser (high 8.7)
- [CVE-2026-26264](https://insights.sbomify.com/CVE-2026-26264/): BACnet Stack WriteProperty decoding length underflow leads to OOB read and crash (high 7.8)
- [CVE-2026-21878](https://insights.sbomify.com/CVE-2026-21878/): BACnet Stack Improperly Limits Pathnames to a Restricted Directory (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-41475 and fix it if it is affected.

What it is: CVE-2026-41475 is a high-severity vulnerability in bacnet-stack, published on 24 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-41475 exists.

Affected product: bacnet-stack. 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-2026-41475/ (Markdown: https://insights.sbomify.com/CVE-2026-41475/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-41475
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-41475
- OSV: https://osv.dev/vulnerability/CVE-2026-41475

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-41475/
Summaries are generated and may contain mistakes; the official description above is the record.