# CVE-2026-102477: Denial of service in Eclipse Vert.x

> Attackers can cause denial of service in Eclipse Vert.x gRPC endpoints by sending compressed messages that expand beyond configured size limits.

- **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:** 15 Oct 2026
- **Updated:** 15 Oct 2026
- **Also known as:** GHSA-3f8m-f8fw-9m74, GHSA-4wvq-75mw-q6cg

## What is CVE-2026-102477?

CVE-2026-102477 is a high-severity denial of service vulnerability in Eclipse Vert.x, published on 15 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In Eclipse Vert.x versions [4.0.0, 4.5.34] or [5.0.0,5.0.12] or [5.1.0,5.1.9] or [5.2.0, 5.2.0], a gRPC endpoint does have a configurable per message maximum size in bytes, however the maximum size applies to the received bytes. When applied to a compressed message, this only applies to the compressed size and not the actual size of the uncompressed content. This can be used to force a gRPC endpoint to allocate more bytes than the value defined by the configuration, making the endpoint vulnerable to compression bomb attacks.

The impacted component is io.vertx:vertx-gprc-server.

Weakness: CWE-409 (Improper Handling of Highly Compressed Data (Data Amplification))

## Which versions are affected by CVE-2026-102477?

It affects 1 product.


Products: Eclipse Vert.x.

## How do I fix CVE-2026-102477?

No fix has been published for CVE-2026-102477 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-102477 being exploited?

There is no known exploitation of CVE-2026-102477 in the wild and no public exploit code.

## Other vulnerabilities in Eclipse Vert.x

- [CVE-2019-17640](https://insights.sbomify.com/CVE-2019-17640/): Path Traversal in Eclipse Vert (critical 9.8)
- [CVE-2018-12542](https://insights.sbomify.com/CVE-2018-12542/): Eclipse Vert.x does not properly neutralize '' (forward slashes) sequences that can resolve to an external location (critical 9.8)
- [CVE-2018-12544](https://insights.sbomify.com/CVE-2018-12544/): Moderate severity vulnerability that affects io.vertx:vertx-core (critical 9.8)
- [CVE-2026-102469](https://insights.sbomify.com/CVE-2026-102469/): Deserialization in Eclipse Vert.x (critical 9.2)
- [CVE-2018-12540](https://insights.sbomify.com/CVE-2018-12540/): High severity vulnerability that affects io.vertx:vertx-web (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-102477 and fix it if it is affected.

What it is: CVE-2026-102477 is a high-severity denial of service vulnerability in Eclipse Vert.x, published on 15 Oct 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-2026-102477 in the wild and no public exploit code.

Affected product: Eclipse Vert.x. 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-2026-102477/ (Markdown: https://insights.sbomify.com/CVE-2026-102477/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-102477
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-102477
- OSV: https://osv.dev/vulnerability/CVE-2026-102477

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-102477/
Summaries are generated and may contain mistakes; the official description above is the record.