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Response snapshot Oct 30, 2026, 19:11 UTC

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VulnerabilityCVE-2026-86146

Inconsistent interpretation of HTTP requests (HTTP request/response smuggling) in the bundled HTTP/1.1 parser of Apache bRPC (version < 1.18.0) on all platforms allows remote...

Inconsistent interpretation of HTTP requests (HTTP request/response smuggling) in the bundled HTTP/1.1 parser of Apache bRPC (version < 1.18.

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-2026-86146 (opens a new tab)

What happened

Inconsistent interpretation of HTTP requests (HTTP request/response smuggling) in the bundled HTTP/1.1 parser of Apache bRPC (version < 1.18.0) on all platforms allows remote attackers to smuggle requests and inject headers when bRPC is deployed behind a proxy or load balancer that parses the same bytes differently.

Root Cause: The bRPC fork of http-parser accepts and acts on several HTTP/1.1 header forms that a conforming front-end either rejects or interprets differently, so the framing or the header set of a message can differ between the front-end and bRPC: 1. A space before the colon of framing headers (e.g.

Content-Length : 5) is accepted; the value still drives bRPC's framing while the reported field name contains the trailing space. 2. Interior spaces inside a Content-Length value (e.g. Content-Length: 1 3) are skipped, so bRPC reads 13 where a front-end reads 1 or rejects the message (same class as CVE-2022-32213 in Node.js). 3. Obsolete line folding (obs-fold, RFC 7230 3.2.

4) of Content-Length and Transfer-Encoding values is accepted, so a folded framing value drives bRPC's framing while a front-end that does not unfold sees a different message. 4. Chunked trailer fields are fed to the same header callbacks as the header section and are merged into the header map like real headers.

Continue reading

A front-end only inspects the header section, so any chunked request can smuggle fields such as Authorization or X-Forwarded-For past it. 5. Transfer-Encoding lists with optional whitespace after a comma (e.g. Transfer-Encoding: gzip, chunked) are not recognized as chunked: such requests are rejected, and responses are read until connection close instead of as chunked, causing response desync.

Affected Scenarios: bRPC server or client communicating over HTTP/1.1 with a front proxy, load balancer, or any peer that parses the message independently. An attacker able to send requests through the front-end can desynchronize the two parsers to smuggle requests, forge headers (e.g. Authorization, X-Forwarded-For) via chunked trailers, or desynchronize responses.

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/3521

Note: After applying the fix, the four header forms above are rejected by default and chunked trailers are dropped instead of merged into the header map.

Two gflags are provided for compatibility: http_allow_obs_fold=true restores acceptance of folded Content-Length/Transfer-Encoding values, and http_strict_header_token=true additionally rejects spaces inside any header field name (not only the ones that decide framing). Legitimate clients that do not use these obsolete forms are unaffected.

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-2026-86146 (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). Inconsistent interpretation of HTTP requests (HTTP request/response smuggling) in the bundled HTTP/1.1 parser of Apache bRPC (version < 1.18.0) on all platforms allows remote... (CVE-2026-86146). https://kevwire.com/record/CVE-2026-86146

MLA

"Inconsistent interpretation of HTTP requests (HTTP request/response smuggling) in the bundled HTTP/1.1 parser of Apache bRPC (version < 1.18.0) on all platforms allows remote... (CVE-2026-86146)." KEVWire, 30 Oct. 2026, kevwire.com/record/CVE-2026-86146.

Chicago

KEVWire. "Inconsistent interpretation of HTTP requests (HTTP request/response smuggling) in the bundled HTTP/1.1 parser of Apache bRPC (version < 1.18.0) on all platforms allows remote... (CVE-2026-86146)." Last modified October 30, 2026. https://kevwire.com/record/CVE-2026-86146.

Evidence summary (plain text)

Inconsistent interpretation of HTTP requests (HTTP request/response smuggling) in the bundled HTTP/1.1 parser of Apache bRPC (version < 1.18.0) on all platforms allows remote... (Oct 21, 2026).
Inconsistent interpretation of HTTP requests (HTTP request/response smuggling) in the bundled HTTP/1.1 parser of Apache bRPC (version < 1.18.0) on all platforms allows remote attackers to smuggle requests and inject headers when bRPC is deployed behind a proxy or load balancer that parses the same bytes differently.

Root Cause:
The bRPC fork of http-parser accepts and acts on several HTTP/1.1 header forms that a conforming front-end either rejects or interprets differently, so the framing or the header set of a message can differ between the front-end and bRPC:
1.
CVSS 7.5 (version 3.1; evidence as of Oct 30, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-86146).
Sources:
NVD CVE-2026-86146: https://nvd.nist.gov/vuln/detail/CVE-2026-86146
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-2026-86146.
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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