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TI-2026-78551 Aliases CVE-2026-56387GHSA-79v7-r95h-fxr5

Remote memory exhaustion in Apache bRPC RTMP AMF parser

Priority MEDIUM 40CWE-770Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-770.

Summary

Apache bRPC before 1.18.0 has a flaw in its RTMP AMF parser. The parser trusts string lengths and array counts declared in input and allocates memory for them before checking that the payload contains that much data (CWE-789). A remote unauthenticated attacker who can reach a bRPC server with RTMP enabled can send a small payload with an excessive declared size to cause excessive memory allocation or resource consumption.

Written with Claude Haiku 5.5 from the sources below · 2026-10-30

Description from the CNA

The RTMP AMF parser in Apache bRPC accepts AMF string lengths and array counts directly from untrusted input. A remote unauthenticated attacker who can reach a bRPC server with RTMP enabled can send a small AMF payload with an excessive declared long string length or array count, causing excessive memory allocation or resource consumption before the parser rejects the incomplete payload. Root Cause: The AMF long string parser resized the destination string to the declared 32-bit length before validating that the stream contained that many bytes. ECMA array and strict array parsers also accepted 32-bit element counts without a configurable upper bound. Affected Scenarios: Deployments that enable the bRPC RTMP server component and accept RTMP traffic from untrusted clients. Direct uses of the AMF parser on untrusted data are also affected. How to Fix: 1. Upgrade bRPC to version 1.18.0, which fixes this issue. 2. Apply this patch:  https://github.com/apache/brpc/pull/3353 Note: The fix introduces configurable AMF parsing limits. The default maximum string size is 64 MiB and the default maximum array element count is 1,048,576. Payloads above these limits are rejected. The limits can be adjusted with amf_max_string_size and amf_max_array_size.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00595 48th percentileScored 2026-11-07
Fix Fixed Apache bRPC (Apache Software Foundation): 1.18.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
ApacheApache bRPCbefore 1.18.01.18.0Patch availableCNA
  • Apache bRPC VendorApache Affected before 1.18.0 Fixed in 1.18.0 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:apache:brpc:*:*:*:*:*:*:*:*——Apache
  • cpe:2.3:a:apache:brpc:*:*:*:*:*:*:*:* Versions — — ·Apache

Remediation

Upgrade Apache bRPC to version 1.18.0, which fixes this issue, or apply pull request 3353 in the apache/brpc repository.

Written with Claude Haiku 5.5 from the sources below · 2026-10-30

  • Fix · CNA Apache bRPC (Apache Software Foundation) Fixed in 1.18.0

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Advisory ·

    Apache bRPC — lists.apache.org/thread/2pf15ojj0vr7rtx95677kgtl1mx3gdgb

    35 records Highest priority Priority MEDIUM 18 MEDIUM, 17 LOW

    Other records, highest priority first

    • TI-2026-78552 Out-of-bounds write in Apache bRPC Redis command parserPriority MEDIUM 49
    • TI-2026-78757 Authentication bypass in Apache bRPC servers using internal_portPriority MEDIUM 48
    • TI-2026-78742 Missing authentication in Apache bRPC streaming RPC framesPriority MEDIUM 48
    Show all 35 records → Advisory →

Timeline

  1. 2026-10-21 Threatist record created from CVE-2026-56387
  2. 2026-10-21 Alias added: GHSA-79v7-r95h-fxr5
  3. 2026-10-30 CVSS score added · CISA ADP
  4. 2026-10-30 CISA SSVC decision points changed
  5. 2026-11-01 Priority changed: LOW → MEDIUM

References

Advisory 1

  • TI-2025-18529 Apache Tomcat: Potential RCE and/or information disclosure and/or information corruption with partial PUT KEVCVSS 3.1CRITICAL 10.0
  • TI-2024-30292 Apache OFBiz: Confused controller-view authorization logic (forced browsing) KEVCVSS 3.1CRITICAL 9.8
  • TI-2024-26062 Apache OFBiz: Unauthenticated endpoint could allow execution of screen rendering code KEVCVSS 3.1CRITICAL 9.8
  • TI-2024-21190 Apache OFBiz: Path traversal leading to RCE KEVCVSS 3.1CRITICAL 9.8
  • TI-2024-18186 Apache HugeGraph-Server: Command execution in gremlin KEVCVSS 3.1CRITICAL 9.8
  • TI-2023-25106 Deserialization of untrusted data in Apache ActiveMQ KEVCVSS 3.1CRITICAL 10.0
See all 4053 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences