CVE-2026-102477: vert.x — Fix

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.

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CVSS v3.1 Score

5.9

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0032

Probability of exploitation

0.25%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-409 CWE-409

Affected Products

Vendor	Product	Versions
eclipse	vert.x	4.5.0 — 4.5.35
eclipse	vert.x	5.0.0 — 5.2.0
eclipse	vert.x	All

References

Advisories & Patches

https://github.com/eclipse-vertx/vertx-grpc/security/advisories/GHSA-4wvq-75mw-q6cg

Other References

https://gitlab.eclipse.org/security/cve-assignment/-/work_items/349

Frequently Asked Questions

What is CVE-2026-102477? +

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. It has a CVSS v3.1 base score of 5.9 (MEDIUM).

How severe is CVE-2026-102477? +

CVE-2026-102477 has a CVSS v3.1 score of 5.9 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0032, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-102477? +

CVE-2026-102477 affects products from eclipse, specifically: vert.x. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-102477? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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