# CVE-2026-56770: libais 0.15 - Out-of-bounds Vector Access in VdmStream::AddLine via Invalid Sequential Message ID

> Remote attackers can crash AIS services or potentially execute code by sending crafted AIVDM sentences with invalid sequential message IDs to libais.

- **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:** 25 Jun 2026
- **Updated:** 25 Jun 2026
- **Also known as:** DEBIAN-CVE-2026-56770, GHSA-2f4m-q55c-v3xr, UBUNTU-CVE-2026-56770

## What is CVE-2026-56770?

CVE-2026-56770 is a high-severity memory corruption vulnerability in schwehr libais, published on 25 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

libais through 0.15 VdmStream::AddLine uses an unchecked sentinel value as a vector index when processing AIS sentences with empty or out-of-range sequential message IDs. Remote attackers can crash services or vessel systems by sending crafted AIVDM sentences over VHF marine radio or IP feeds, causing out-of-bounds memory access and potential corruption.

Weakness: CWE-129 (Improper Validation of Array Index)

## Which versions are affected by CVE-2026-56770?


## How do I fix CVE-2026-56770?

No fix has been published for CVE-2026-56770 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-56770 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-56770 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-56770 and fix it if it is affected.

What it is: CVE-2026-56770 is a high-severity memory corruption vulnerability in schwehr libais, published on 25 Jun 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-2026-56770 exists.

Affected product: schwehr libais. 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-2026-56770/ (Markdown: https://insights.sbomify.com/CVE-2026-56770/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-56770
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-56770
- OSV: https://osv.dev/vulnerability/CVE-2026-56770

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-56770/
Summaries are generated and may contain mistakes; the official description above is the record.