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TI-2026-78747 Aliases CVE-2026-82230GHSA-5pph-8c9p-w8p3

Unbounded recursion in Apache bRPC mcpack2pb parser crashes server

Priority MEDIUM 40CWE-674Published · 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-674.

Summary

Apache bRPC before 1.18.0 on all platforms has uncontrolled recursion in its mcpack2pb parser (CWE-674), which parses nested mcpack objects and arrays without a depth limit. A remote attacker can crash the server by sending deeply nested mcpack data when it serves nshead_mcpack, ubrpc or public_pbrpc requests with a recursive protobuf message.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Description from the CNA

Uncontrolled recursion in the mcpack2pb component in Apache bRPC (version < 1.18.0) on all platforms allows remote attackers to make the server crash via sending deeply nested mcpack data. Root Cause: The bRPC mcpack2pb parser (used to serve nshead_mcpack / ubrpc / public_pbrpc requests) recursively parses nested objects and arrays without any depth limit. For a protobuf message that references itself (e.g. a repeated message field), the generated parser recurses once per nesting level of the incoming mcpack object. A deeply nested request makes the recursion grow unbounded, overflow the stack and crash the process. Affected Scenarios: Use bRPC server with a recursive-schema protobuf message to serve nshead_mcpack / ubrpc / public_pbrpc requests from untrusted network. How to Fix: (Choose one of the following options) 1. Upgrade bRPC to version 1.18.0, which fixes this issue. 2. Apply this patch: https://github.com/apache/brpc/pull/3499 Note: No matter which option you choose, you should know that the fix enforces the documented parsing depth limit MAX_DEPTH (128) on the parse path, the same limit the serializer already applies. If your requests contain mcpack messages nested deeper than 128 levels, the request will be failed after applying the fix.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0055 46th 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 1.18.0, which fixes the issue. Alternatively, apply the patch in pull request 3499 of the apache/brpc repository. The fix enforces a parsing depth limit of MAX_DEPTH (128), so mcpack messages nested deeper than 128 levels are rejected.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

  • 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-2026-82230
  2. 2026-10-21 CVSS score added · CISA ADP
  3. 2026-10-21 CISA SSVC decision points changed
  4. 2026-10-21 Alias added: GHSA-5pph-8c9p-w8p3
  5. 2026-10-23 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

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