# CVE-2026-56788: RTKLIB 2.4.3 - Out-of-bounds Read via Negative Array Index in getcodepri

> Attackers can cause crashes or leak memory by providing crafted RINEX files to RTKLIB, affecting applications using this GNSS library.

- **Severity:** Medium 4.8 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 25 Jun 2026
- **Updated:** 14 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-56788, GHSA-m65p-fp8q-q43h, UBUNTU-CVE-2026-56788

## What is CVE-2026-56788?

CVE-2026-56788 is a medium-severity memory corruption vulnerability in tomojitakasu RTKLIB, published on 25 Jun 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

RTKLIB through 2.4.3 contains an out-of-bounds read vulnerability in getcodepri function when processing unrecognized RINEX observation codes, allowing attackers to trigger denial of service. Crafted RINEX files with unknown observation types cause negative array indexing into the codepris table, resulting in reliable crashes and potential memory disclosure of adjacent global data.

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

## Which versions are affected by CVE-2026-56788?

It affects 1 product.


Products: Rtklib Rtklib.

## How do I fix CVE-2026-56788?

No fix has been published for CVE-2026-56788 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-56788 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-56788 exists.

## Other vulnerabilities in tomojitakasu RTKLIB

- [CVE-2026-56786](https://insights.sbomify.com/CVE-2026-56786/): RTKLIB 2.4.3 - Out-of-bounds Write in decode_type1033 via Crafted RTCM3 Message (critical 9.3)
- [CVE-2026-56789](https://insights.sbomify.com/CVE-2026-56789/): RTKLIB 2.4.3 - Heap Buffer Overflow and Stack Read via Oversized RINEX Epoch Satellite Count (high 7.1)
- [CVE-2026-56787](https://insights.sbomify.com/CVE-2026-56787/): RTKLIB 2.4.3 - Off-by-One Out-of-Bounds Read in decode_ssr3 via RTCM3 SSR Message (medium 6.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-56788 and fix it if it is affected.

What it is: CVE-2026-56788 is a medium-severity memory corruption vulnerability in tomojitakasu RTKLIB, published on 25 Jun 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-56788 exists.

Affected product: tomojitakasu RTKLIB. 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-2026-56788/ (Markdown: https://insights.sbomify.com/CVE-2026-56788/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-56788
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-56788
- OSV: https://osv.dev/vulnerability/CVE-2026-56788

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-56788/
Summaries are generated and may contain mistakes; the official description above is the record.