9.1 CRITICAL
- CVSS version (CVSS): 4.0
- Attack Vector (AV): Network (N)
- Attack Complexity (AC): Low (L)
- Attack Requirement (AT): Present (P)
- Privileges Required (PR): None (N)
- User Interaction (UI): None (N)
- Vulnerable System Impact Confidentiality (VC): High (H)
- Vulnerable System Impact Integrity (VI): High (H)
- Vulnerable System Impact Availability (VA): None (N)
- Subsequent System Impact Confidentiality (SC): None (N)
- Subsequent System Impact Integrity (SI): None (N)
- Subsequent System Impact Availability (SA): None (N)
- Modified Attack Vector (MAV): Network (N)
- Modified Attack Complexity (MAC): Low (L)
- Modified Attack Requirement (MAT): Present (P)
- Modified Privileges Required (MPR): None (N)
- Modified User Interaction (MUI): None (N)
- Modified Vulnerable System Impact Confidentiality (MVC): High (H)
- Modified Vulnerable System Impact Integrity (MVI): High (H)
- Modified Vulnerable System Impact Availability (MVA): None (N)
- Modified Subsequent System Impact Confidentiality (MSC): Negligible (N)
- Modified Subsequent System Impact Integrity (MSI): Negligible (N)
- Modified Subsequent System Impact Availability (MSA): Negligible (N)
- Safety (S): Not Defined (X)
- Automatable (AU): Not Defined (X)
- Recovery (R): Not Defined (X)
- Value Density (V): Not Defined (X)
- Vulnerability Response Effort (RE): Not Defined (X)
- Provider Urgency (U): Not Defined (X)
- Confidentiality Req. (CR): Not Defined (X)
- Integrity Req. (IR): Not Defined (X)
- Availability Req. (AR): Not Defined (X)
- Exploit Maturity (E): Not Defined (X)
Activity log
- Created & dismissed (no matching packages found) suggestion
Netty: SNI Routing Bypass via Fragmented TLS ClientHello Causing Fallback to Default SslContext
Netty is an asynchronous, event-driven network application framework. Prior to 4.1.137.Fina and 4.2.17.Final, io.netty.handler.ssl.SslClientHelloHandler#decode checks the wrong offset before reading the four-byte TLS handshake header, so a ClientHello whose handshake header spans records can cause an IndexOutOfBoundsException and invoke select(ctx, null). This selects the default SslContext instead of the SNI-specific context. In deployments where per-SNI clientAuth=REQUIRE is the sole mutual TLS gate, the default SslContext uses clientAuth=NONE or clientAuth=OPTIONAL, and no application-layer certificate verification exists, an unauthenticated remote attacker can bypass the protected route's mutual TLS requirement. This issue is fixed in versions 4.1.137.Final and 4.2.17.Final.
References
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https://github.com/netty/netty/security/advisories/GHSA-c4c3-7fpv-j4q5 x_refsource_CONFIRM
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https://github.com/netty/netty/pull/17213 x_refsource_MISC
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https://github.com/netty/netty/pull/17217 x_refsource_MISC
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https://github.com/netty/netty/releases/tag/netty-4.1.137.Final x_refsource_MISC
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https://github.com/netty/netty/releases/tag/netty-4.2.17.Final x_refsource_MISC
Affected products
- ==< 4.1.137.Final
- ==>= 4.2.0.Final, < 4.2.17.Final