CVE•Published 2026-07-21•Modified 2026-07-30•0 articles on news•5 live references•NVD data

CVE-2026-56820Netty · Netty

Vulnerability data via NVD (ingested)

CVSS v3.1

7.4

HIGH

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

EPSS percentile

Exploit Prediction Scoring System · top 92% of all CVEs

Weaknesses (CWE)

CWE-295Improper Certificate Validation

Description

Netty is a network application framework for development of protocol servers and clients. In versions 4.2.0.Final through 4.2.15.Final and prior to 4.1.135.Final, `OcspClient` does not validate that the `CertificateID` in an OCSP response matches the requested `CertificateID`, which can lead to replay attack. `OcspClient.validateResponse` accepts a legitimately signed `GOOD` status response for an unrelated certificate issued by the same CA, allowing bypass of revocation checks for another certificate. This issue is fixed in versions 4.1.136.Final and 4.2.16.Final.

Timeline

Published 2026-07-21

Modified 2026-07-30

External references

NVD MITRE Exploit-DB GitHub PoC VulnCheck

Search for exposed instances

Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).

Shodan · vuln tag0 hosts

vuln:CVE-2026-56820

Hosts Shodan has explicitly fingerprinted as vulnerable.

Shodan · product

product:"Netty Netty"

All exposed Netty Netty instances — cross-reference with the CVE's affected-version range.

Shodan · banner/body mention

http.html:"Netty"

HTTP body or banner mentions "Netty" — catches deploys Shodan didn't identify as a product.

More intel sources (5)

Shodan report

vuln:CVE-2026-56820