# CVE-2026-75584: ION-DTN < 4.2.1-a.1 Denial of Service via canonicalizePayloadBlock() Assertion

> Unauthenticated remote attackers can crash the ION-DTN process by sending a BPv7 bundle with a zero-length payload, causing an assertion failure.

- **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:** 10 Sep 2026
- **Updated:** 18 Sep 2026
- **Also known as:** GHSA-9vgc-2r6g-6qwf

## What is CVE-2026-75584?

CVE-2026-75584 is a high-severity denial of service vulnerability in nasa-jpl ION-DTN, published on 10 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

ION-DTN before 4.2.1-a.1 contains a denial of service vulnerability that allows unauthenticated remote attackers to crash the ION process by sending a BPv7 bundle with a zero-length payload. The canonicalizePayloadBlock() function in bpsec_util.c passes bundle->payload.length to zco_clone() without validating it against zero, causing a failed CHKZERO assertion that triggers sm_Abort() and terminates the process with SIGABRT before any HMAC verification occurs, requiring no valid key or credential to exploit.

Weakness: CWE-617 (Reachable Assertion)

## Which versions are affected by CVE-2026-75584?


## How do I fix CVE-2026-75584?

No fix has been published for CVE-2026-75584 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-75584 being exploited?

There is no known exploitation of CVE-2026-75584 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-75584 and fix it if it is affected.

What it is: CVE-2026-75584 is a high-severity denial of service vulnerability in nasa-jpl ION-DTN, published on 10 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-75584 in the wild and no public exploit code.

Affected product: nasa-jpl ION-DTN. 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-2026-75584/ (Markdown: https://insights.sbomify.com/CVE-2026-75584/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-75584
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-75584
- OSV: https://osv.dev/vulnerability/CVE-2026-75584

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-75584/
Summaries are generated and may contain mistakes; the official description above is the record.