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Response snapshot Oct 30, 2026, 17:36 UTC

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VulnerabilityCVE-2026-81755

Uncontrolled resource consumption in the streaming RPC component of Apache bRPC (version < 1.18.0) allows a remote attacker to exhaust server memory and cause denial of service by...

Uncontrolled resource consumption in the streaming RPC component of Apache bRPC (version < 1.18.0) allows a remote attacker to exhaust server memory and cause denial of service by sending a single RPC request that declares an excessive number of streams.

At a glance

Exploited
Not known
Severity
7.5 High (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-81755 (opens a new tab)

What happened

Uncontrolled resource consumption in the streaming RPC component of Apache bRPC (version < 1.18.0) allows a remote attacker to exhaust server memory and cause denial of service by sending a single RPC request that declares an excessive number of streams.

Root Cause: In the streaming RPC feature, a client can declare multiple streams in one RPC request by putting extra stream identifiers into the repeated field stream_settings.extra_stream_ids of the RPC meta. On the server side, StreamAccept creates one response stream for every stream identifier declared by the request, without limiting the number of streams accepted in a single RPC.

The request body size is only bounded by max_body_size (default 64MB), which is enough to carry millions of stream identifiers. Each accepted stream allocates its own bthread execution queue and associated resources, so a single crafted request can make the server create a huge number of streams and exhaust memory, leading to denial of service.

Affected Scenarios: Use a bRPC server that serves streaming RPC and calls StreamAccept to accept streams from untrusted clients.

Continue reading

How to Fix: (Choose one of the following options) 1. Upgrade bRPC to the 1.18.0 version. 2. Apply this patch: https://github.com/apache/brpc/pull/3493

Note: The fix adds a new gflag stream_max_streams_per_request with a default value of 64. Requests declaring more streams than the limit are rejected before any response stream is created. Applications that legitimately need to accept more than 64 streams in one RPC must raise this flag; otherwise such requests will fail after applying the fix.

Scores and how they were measured

CVSS base severity

7.5

Version 3.1As of

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

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Sources

  1. Primary source

    NVD CVE-2026-81755 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 30). Uncontrolled resource consumption in the streaming RPC component of Apache bRPC (version < 1.18.0) allows a remote attacker to exhaust server memory and cause denial of service by... (CVE-2026-81755). https://kevwire.com/record/CVE-2026-81755

MLA

"Uncontrolled resource consumption in the streaming RPC component of Apache bRPC (version < 1.18.0) allows a remote attacker to exhaust server memory and cause denial of service by... (CVE-2026-81755)." KEVWire, 30 Oct. 2026, kevwire.com/record/CVE-2026-81755.

Chicago

KEVWire. "Uncontrolled resource consumption in the streaming RPC component of Apache bRPC (version < 1.18.0) allows a remote attacker to exhaust server memory and cause denial of service by... (CVE-2026-81755)." Last modified October 30, 2026. https://kevwire.com/record/CVE-2026-81755.

Evidence summary (plain text)

Uncontrolled resource consumption in the streaming RPC component of Apache bRPC (version < 1.18.0) allows a remote attacker to exhaust server memory and cause denial of service by... (Oct 21, 2026).
Uncontrolled resource consumption in the streaming RPC component of Apache bRPC (version < 1.18.0) allows a remote attacker to exhaust server memory and cause denial of service by sending a single RPC request that declares an excessive number of streams.

Root Cause:
In the streaming RPC feature, a client can declare multiple streams in one RPC request by putting extra stream identifiers into the repeated field stream_settings.extra_stream_ids of the RPC meta.
CVSS 7.5 (version 3.1; evidence as of Oct 30, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-81755).
Sources:
NVD CVE-2026-81755: https://nvd.nist.gov/vuln/detail/CVE-2026-81755
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-30T14:50:59.566Z&lastModEndDate=2026-10-30T16:25:56.397Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-30T13:52:33.301Z&lastModEndDate=2026-10-30T15:50:56.559Z&resultsPerPage=500&startIndex=0
Record ID: CVE-2026-81755.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 30, 2026, 16:25 UTC. Ingestion is not an independent editorial investigation.

NVD status: Deferred. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

Record detail