CVE-2026-42578
Is CVE-2026-42578 real, exploitable, or a false positive? Here's the community verdict.
signals
public sources
High CVSS base score, but low real-world exploitation probability (EPSS). Likely less urgent than the score implies.
scanner noise
anonymous, aggregated from real reports · via Denoizr| Scanner | Flagged in | Turned out noise |
|---|---|---|
| Mend | 2 scans | 0% |
How often this CVE was flagged by each scanner and how much turned out to be noise (false positives), aggregated anonymously from de-noised reports. Higher noise means the alert is more often not a real risk — verify your exposure.
baseline read
auto · not a community verdict
Real, but low real-world risk
A genuine vulnerability on paper, but EPSS shows little real-world exploitation — the base score may overstate urgency. This is not the same as a false positive.
Based on CVSS · FIRST EPSS
Confirm or dispute →CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty's HttpProxyHandler constructs HTTP CONNECT requests with header validation explicitly disabled. The newInitialMessage() method creates headers using DefaultHttpHeadersFactory.headersFactory().withValidation(false), then adds user-provided outboundHeaders without any CRLF validation. This allows an attacker who can influence the outbound headers to inject arbitrary HTTP headers into the CONNECT request sent to the proxy server. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.
References
Published
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In your experience, is this finding real and exploitable?
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Field notes & remediation
Verdicts are the quick signal. Notes are the evidence and fixes behind them.
- 0
This scores high on paper (CVSS 7.5) but the real-world signal is low. It is not in CISA KEV and no public exploit was found, and near-term exploitation looks unlikely (EPSS about 1%). Verify your own exposure before treating it as urgent. It is reachable over the network with no authentication and no user interaction, which is the most dangerous profile. Not an emergency for most teams, but patch it in your normal cycle and check whether the affected component is actually exposed in your setup.
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Related CVEs
Same weakness: CWE-113.
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