CVE-2026-48040 in netty-incubator-codec-ohttp
Summary
by MITRE • 06/04/2026
The netty incubator codec.bhttp is a java language binary http parser. The library implements Oblivious HTTP (RFC 9458) using BoringSSL's HPKE C library via JNI. When deriving native memory addresses for cryptographic operations versions prior to 0.0.22.Final provide a fallback path for direct ByteBufs that do not expose their memory address through `hasMemoryAddress()`. This fallback occurs when `sun.misc.Unsafe` is unavailable to Netty — for example, when the JVM is started with `-Dio.netty.noUnsafe=true`, when a SecurityManager restricts Unsafe access, or when running on non-HotSpot JVMs. In these configurations, Netty's default `PooledByteBufAllocator` returns `PooledDirectByteBuf` instances for which `hasMemoryAddress()` returns false. Under the enabling JVM configuration, an unauthenticated network attacker can cause the OHTTP gateway to corrupt memory belonging to other concurrent connections and disclose the contents of adjacent pooled direct buffers by triggering cryptographic operations with crafted OHTTP requests. The corruption occurs regardless of whether the AEAD tag verification succeeds, as BoringSSL zeroizes the output buffer on failure. The information disclosure path provides the attacker with the encryption key needed to extract the leaked data. This violates the confidentiality and integrity of all connections sharing the same Netty buffer arena. Version 0.0.22.Final fixes the issue.
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Analysis
by VulDB Data Team • 06/04/2026
The vulnerability resides in the netty incubator codec.bhttp library which implements Oblivious HTTP (RFC 9458) using BoringSSL's HPKE C library via JNI. This library serves as a binary HTTP parser in java environments and handles cryptographic operations through native memory addressing mechanisms. The flaw manifests specifically in versions prior to 0.0.22.Final where the implementation fails to properly handle memory address derivation for cryptographic operations. When the library encounters direct ByteBuf instances that do not expose their memory address through the hasMemoryAddress() method, it attempts to fall back to alternative memory access patterns. This fallback mechanism becomes problematic when sun.misc.Unsafe is unavailable to Netty, which occurs under specific JVM configurations including those started with -Dio.netty.noUnsafe=true, when SecurityManager restricts Unsafe access, or when running on non-HotSpot JVMs. The affected configuration causes Netty's default PooledByteBufAllocator to return PooledDirectByteBuf instances where hasMemoryAddress() returns false, creating a critical gap in the memory management approach.
The operational impact of this vulnerability represents a severe security flaw that allows unauthenticated network attackers to compromise the integrity and confidentiality of concurrent connections sharing the same Netty buffer arena. When attackers trigger cryptographic operations with crafted OHTTP requests under the enabling JVM configuration, they can corrupt memory belonging to other concurrent connections through improper memory addressing. This memory corruption occurs regardless of AEAD tag verification success since BoringSSL zeroizes the output buffer on failure, ensuring that even failed cryptographic operations can be exploited. The information disclosure path provides attackers with encryption keys necessary to extract leaked data from adjacent pooled direct buffers, fundamentally undermining the security boundaries between concurrent connections. This vulnerability directly violates the confidentiality and integrity principles as defined by the CIA triad and represents a classic example of memory safety issues that can lead to privilege escalation and data exposure across multiple network sessions.
The technical implementation flaw stems from the library's inadequate handling of memory address resolution in restricted JVM environments where Unsafe operations are disabled. This creates a path for attackers to manipulate memory layouts through carefully crafted HTTP requests that trigger cryptographic operations on buffer instances lacking proper memory address exposure. The vulnerability aligns with CWE-121 Stack-based Buffer Overflow and CWE-125 Out-of-bounds Read categories, as the improper memory addressing leads to both corruption and information disclosure. From an ATT&CK framework perspective, this represents a privilege escalation technique through memory corruption (T1068) and information gathering via data exposure (T1005). The fix implemented in version 0.0.22.Final addresses the core issue by properly handling native memory addresses for cryptographic operations regardless of the underlying JVM configuration, ensuring that all buffer types receive appropriate memory management treatment. Organizations should immediately upgrade to the fixed version and implement monitoring for suspicious cryptographic operation patterns that might indicate exploitation attempts. Additionally, system administrators should review JVM startup parameters to ensure that -Dio.netty.noUnsafe=true is not inadvertently enabled in production environments without proper security controls in place.