CVE-2026-62243 (GCVE-0-2026-62243)

Vulnerability from cvelistv5 – Published: 2026-08-22 12:26 – Updated: 2026-08-24 19:36
VLAI
Title
Netty 4.2.0 through 4.2.16 TLS Hostname Verification Bypass
Summary
Netty (io.netty:netty-handler) versions from 4.2.0.Final through 4.2.16.Final and versions through 4.1.136.Final disable TLS hostname verification on the SslProvider.OPENSSL client path when a plain (non-extended) X509TrustManager is used and Unsafe-based trust-manager wrapping is unavailable (Java 25+). In this configuration the OpenSSL client does not perform hostname verification, allowing a man-in-the-middle attacker to present a certificate issued for a different hostname that is accepted without validation. Fixed in 4.2.17.Final and 4.1.137.Final.
Severity
8.7 (High)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-24 19:36 UTC
CWE
  • CWE-297 - Improper Validation of Certificate with Host Mismatch
Assigner
VulnCheck CNA under the mitre root
CNA scorecard B 84/100 over 6906 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
netty netty Affected: 4.2.0.Final , < 4.2.16.Final (custom)
Unaffected: 4.2.16.Final (custom)
guessed Create a notification for this product.
netty netty Affected: 0 , < 4.1.137.Final (custom)
Unaffected: 4.1.137.Final (custom)
guessed Create a notification for this product.
Date Public
2026-08-07 00:00
Credits
violetagg
Show details on NVD website
To clipboard 

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

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    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.