CVE-2026-62243: netty
Vulnerability summary
CVE-2026-62243 is a high (CVSS 8.7) vulnerability in netty. EPSS estimates a 0.15% chance of exploitation in the next 30 days, higher than 4.2% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 5 · Related 2Timeline
- 22-08-2026PublishedVulnerability first disclosed.
- 24-08-2026Last modifiedVulnerability information updated.
Description
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.
CVSS metrics
7 scores · 4 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
- OSV · DebianEcosystem advisory · calculated8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- NVDNIST8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- NVDNIST7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS trend
Probability
0.15%
Chance of exploitation in the next 30 days
Percentile
4%
Versus all other CVEs
30-day change
0.00 pp
From 0.15% on 18-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Chainguard3 products
- logstash-8.19< 8.19.21-r0
- logstash-8.19-iamguarded-compat< 8.19.21-r0
- logstash-8.19-with-output-opensearch< 8.19.21-r0
Debian1 product
- nettyAll versions (No fix recorded)
Netty1 product
- netty≥ 4.2.0.Final, < 4.2.16.Final | < 4.1.137.Final
Ubuntu1 product
- nettyAll versions (No fix recorded)
4 vendors · 6 products
References
5 links- www.vulncheck.com/advisories/netty-through-tls-hostname-verification-bypassThird Party Advisory
