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CVE.org (no NVD analysis yet)· CNA apache

CVE-2026-82230: Apache bRPC: Stack Exhaustion via Unbounded Recursion in mcpack2pb Parser

Noroxi assessment

Priority: Monitor (action score 30/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.55% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Apache Software Foundation Apache bRPC 1.18.0.

Low priority for now. Upgrade to Apache Software Foundation Apache bRPC 1.18.0 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.5 · v3.1—No exploit Fix available
Published
Oct 21, 2026
Updated
Oct 26, 2026
EPSS
0.5% · 46th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (apache). Independent of NVD's CPE analysis and usually ahead of it.

  • Apache Software Foundation Apache bRPC

    • before 1.18.0affected · semver

Same product

apache software foundation: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-86249Apache bRPC: Authentication bypass when a server sets ServerOptions.internal_port and ServerOptions.auth
    36Monitor
  • CVE-2026-78334Apache bRPC: Missing Authentication for Streaming RPC Frames
    36Monitor
  • CVE-2026-56388Apache bRPC: Out-of-Bounds Write in Redis Command Parser
    36Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-81755Oct 21, 2026 · Apache bRPC: Uncontrolled Resource Consumption via Excessive Streams in a Single RPC Request
    30Monitor
  • ← EarlierCVE-2026-82210Oct 21, 2026 · Apache bRPC: Remote denial of service (crash) via malformed stream feedback frames
    30Monitor
  • Later →CVE-2026-82231Oct 21, 2026 · Apache bRPC: Malformed Thrift T_EXCEPTION reply causes process termination in Thrift client
    30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Apache Software Foundation Apache bRPC1.18.0Vendor (CNA)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 10, 2026+20 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-544250 days apartApache bRPC: Stack Exhaustion via Recursive HPACK Dynamic Table Size Update Decoding
    30Monitor
  • CVE-2026-544260 days apartApache bRPC: Stack Exhaustion via Unbounded Recursion in Redis Reply Parser
    30Monitor
  • CVE-2026-544270 days apartApache bRPC: Stack Exhaustion via Unbounded Recursion in AMF Parser
    30Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-674 · Uncontrolled Recursion

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. CVSS— → 7.5
  2. Severity— → high
  3. SSVC exploitation— → none
  4. Exploit maturity— → none
  5. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records