CVE-2026-56387 is a vulnerability in Apache bRPC's RTMP AMF parser where untrusted input can specify excessive string lengths or array counts, leading to excessive memory allocation or resource consumption. This affects deployments with the bRPC RTMP server enabled and accepting RTMP traffic from untrusted clients. The issue is fixed in Apache bRPC version 1.18.0 by introducing configurable limits on AMF string size and array element count.
Integer underflow and out-of-bounds read in the HTTP/2 server DATA frame parser in Apache bRPC allows an unauthenticated remote attacker to cause denial of service by sending a malformed DATA frame with the PADDED flag set and a zero-length payload.
Root Cause:
The HTTP/2 DATA frame handler computed the fragment size from the attacker-controlled payload length and, when the PADDED flag was present, decremented the fragment size before ensuring that the frame contained the mandatory pad length byte. A zero-length padded DATA frame could therefore underflow the unsigned fragment size and read the pad length byte past the end of the frame buffer.
Affected Scenarios:
Apache bRPC servers that accept HTTP/2 traffic are affected when a remote client can send crafted HTTP/2 frames to the server. HTTP/2 may be reached through cleartext h2c detection on an HTTP port or through TLS ALPN negotiation.
How to Fix:
(Choose one of the following options)
1. Upgrade Apache bRPC to version 1.18.0, which fixes this issue.
2. Apply this patch: https://github.com/apache/brpc/pull/3325
Note:
The fix validates that a padded DATA frame has enough payload bytes for the pad length field before decrementing the fragment size or reading the pad length byte. Malformed zero-length padded DATA frames are rejected with HTTP/2 FRAME_SIZE_ERROR.
Apache bRPC versions prior to 1.18.0 contain an uncontrolled recursion vulnerability in the AMF parser. This flaw allows a remote RTMP peer to crash the bRPC process by sending deeply nested AMF objects or arrays, which exhausts the native stack. The vulnerability affects applications using bRPC RTMP support that parse AMF data from untrusted sources. The issue is fixed in version 1.18.0 by introducing a configurable maximum AMF nesting depth, defaulting to 128.
Apache bRPC versions prior to 1.18.0 contain an uncontrolled recursion vulnerability in the Redis reply parser. This flaw allows a remote Redis server peer to crash a bRPC Redis client by sending a deeply nested RESP array reply, causing the parser to recurse without a depth limit. The issue is fixed in version 1.18.0 by adding a configurable maximum reply depth, defaulting to 128, which rejects overly nested replies.
Apache bRPC versions prior to 1.18.0 contain an uncontrolled recursion vulnerability in the HTTP/2 HPACK decoder. This flaw allows remote attackers to cause a denial of service by sending a crafted HTTP/2 header block with many consecutive Dynamic Table Size Update entries, which triggers excessive recursive calls and exhausts the thread stack. The issue is fixed in version 1.18.0 by changing the decoding process to iterative parsing.
Apache bRPC versions up to 1.17.0 contain an improper authentication vulnerability that allows remote unauthenticated attackers to bypass authentication on protected non-builtin HTTP endpoints. This occurs when ServerOptions.auth is enabled and builtin HTTP services are exposed on the public listener. An attacker can send a builtin HTTP request first on an HTTP/1.1 keep-alive connection, causing the connection to be treated as authenticated for subsequent requests. The issue is fixed in Apache bRPC version 1.18.0.
The Legacy Pipe receiver protocol (handshake / sendPipeData) uses a
hardcoded SUPER_USER (root) identity when executing data loading and
deletion operations. A user with only SYSTEM-level privileges (such as
USE_PIPE or MAINTAIN) who does NOT have WRITE_DATA or DELETE_DATA
permissions on target databases can send specially crafted PipeData
messages through the Legacy Pipe API, resulting in data loading/deletion
operations executed as root — effectively bypassing IoTDB's permission
model entirely.
This issue affects Apache IoTDB: from 2.0.0 before 2.0.11.
Users are recommended to upgrade to version 2.0.11, which fixes the issue.
Missing authentication for critical function vulnerability in Apache IoTDB.
This issue affects Apache IoTDB: from 2.0.0 before 2.0.11.
Users are recommended to upgrade to version 2.0.11, which fixes the issue.
Uncontrolled Resource Consumption vulnerability in Apache IoTDB JDBC driver.
This issue affects Apache IoTDB JDBC driver: from 1.3.3 before 2.0.11.
Users are recommended to upgrade to version 2.0.11, which fixes the issue.
An authentication bypass vulnerability exists in Apache IoTDB's Thrift RPC service
This issue affects Apache IoTDB: from 2.0.0 before 2.0.11.
Users are recommended to upgrade to version 2.0.11, which fixes the issue.
Insufficient filtering of credentials in the _replicator database in Apache CouchDB 3.5.2 and below on all platforms allows an authenticated user to read replication credentials of other users’ replications, not just their own.
Users are recommended to upgrade to version 3.5.3, which fixes this issue.
Missing authorisation checks in chttpd in Apache CouchDB 3.5.2 and below on all platforms allows any request to read the full contents of a prefixed _user or _replicator database via an unauthorised API endpoint.
The use of prefixed system databases is very rare.
Users are recommended to upgrade to version 3.5.3, which fixes this issue.
Unsafe binary deserialisation in chttpd in Apache CouchDB 3.5.2 and below on all platforms allows an authenticated user to cause a denial of service via memory exhaustion.
Users are recommended to upgrade to version 3.5.3, which fixes this issue.
A missing circuit-breaker in the replicator in Apache CouchDB 3.5.2 and below on all platforms allows the owner of a replication source or target to cause a denial of service via creating an infinite HTTP redirect loop.
Users are recommended to upgrade to version 3.5.3, which fixes this issue.
An unlimited gzip decompression routine in chttpd in Apache CouchDB 3.5.2 and below on all platforms allows any remote client to cause a denial of service via memory exhaustion.
Users are recommended to upgrade to version 3.5.3, which fixes this issue.
An unvalidated runtime configuration value in Apache CouchDB 3.5.2 and below on all platforms allows a CouchDB server admin to run arbitrary shell commands as the CouchDB operating system user.
Users are recommended to upgrade to version 3.5.3, which fixes this issue.
Buffer under-read vulnerability in Apache Tomcat meant that a large non-blocking write could result in the response body being split between the current request and the next request received on that connection leading most likely to failure of the second request and possibly leakage of data from the first response to the second.
This issue affects Apache Tomcat: from 11.0.0-M25 through 11.0.26.
Users are recommended to upgrade to version 11.0.27, which fixes the issue.
Incorrect object recycling and re-use vulnerability in Apache Tomcat affecting HTTP/2 processing of asynchronous servlets can trigger request and/or response mix-up between users.
This issue affects Apache Tomcat: from 11.0.22 through 11.0.26, from 10.1.55 through 10.1.60, from 9.0.118 through 9.0.122.
Users are recommended to upgrade to version 11.0.27, 10.1.61 or 9.0.123, which fixes the issue.
A missing critical step in authentication vulnerability in Apache Tomcat when the JNDI realm was configured with with a non GSSAPI SASL authentication mechanism allowed attackers to authenticate without providing the correct password.
This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.26, from 10.1.0-M1 through 10.1.60, from 9.0.0.M1 through 9.0.122.
The following versions were EOL at the time the CVE was created but are known to be affected: from 8.5.0 through 8.5.100, from 7.0.0 through 7.0.109. Other unsupported versions may also be affected.
Users are recommended to upgrade to version 11.0.27, 10.1.61 or 9.0.123, which fix the issue.
Incomplete cleanup vulnerability in Apache Tomcat could cause TLS 1.3 connections to fail intermittently.
This issue affects Apache Tomcat: from 11.0.0-M21 through 11.0.26, from 10.1.25 through 10.1.60, from 9.0.90 through 9.0.122.
Users are recommended to upgrade to version 11.0.27, 10.1.61 or 9.0.123, which fix the issue.