CVE-2026-73276Network attack vectorHinoki check available

HTTP request smuggling via malformed header handling

Published Sep 1, 2026 · Updated Sep 1, 2026

HTTP request smuggling in Erlang/OTP inets httpd allows remote attackers to inject pipelined requests through a reverse proxy. The parser silently drops a Content-Length header containing whitespace before its colon, defaults the body length to zero, and treats body bytes as a second request. Exploitation requires the default httpd configuration behind a reverse proxy that accepts the malformed header; affected inets ranges are 7.1.2 before 9.3.2.7, 9.4 before 9.6.2.3, and 9.7 before 9.7.2.

CVSS severity8.3
High
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

HTTP request smuggling in Erlang/OTP inets httpd allows remote attackers to inject pipelined requests through a reverse proxy. The parser silently drops a Content-Length header containing whitespace before its colon, defaults the body length to zero, and treats body bytes as a second request. Exploitation requires the default httpd configuration behind a reverse proxy that accepts the malformed header; affected inets ranges are 7.1.2 before 9.3.2.7, 9.4 before 9.6.2.3, and 9.7 before 9.7.2.

The record

CVE
CVE-2026-73276
Published
Sep 1, 2026
Updated
Sep 1, 2026
Vendor
Erlang
Product
Erlang/OTP
Classifications
CWE-444, CAPEC-33, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 1, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=22.2 <27.3.4.17
  2. Affected versionversion=28.0 <28.5.0.6
  3. Affected versionversion=29.0 <29.0.6
  4. Affected versionversion=7.1.2 <9.3.2.7
  5. Affected versionversion=9.4 <9.6.2.3
  6. Affected versionversion=9.7 <9.7.2
  7. Affected versionversion=c06db0bedf49a9b40725745e73fa82e562612815 <* changes=[{"at":"60add5a19e2154560fdff3fe92dba14a68bbd683","status":"unaffected"},{"at":"6cd995e34d3bb3d36dd278dded2d62c25e71820c","status":"unaffected"},{"at":"c285240c6e4b93960c5dc4f17ba04e6fdfb27a0f","status":"unaffected"}]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Erlang · Erlang/OTPversion=22.2 <27.3.4.17; version=28.0 <28.5.0.6; version=29.0 <29.0.6; version=7.1.2 <9.3.2.7; version=9.4 <9.6.2.3; version=9.7 <9.7.2; version=c06db0bedf49a9b40725745e73fa82e562612815 <* changes=[{"at":"60add5a19e2154560fdff3fe92dba14a68bbd683","status":"unaffected"},{"at":"6cd995e34d3bb3d36dd278dded2d62c25e71820c","status":"unaffected"},{"at":"c285240c6e4b93960c5dc4f17ba04e6fdfb27a0f","status":"unaffected"}]

Published CVSS scores

8.3Erlang Ecosystem FoundationCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-444Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
CAPEC-33HTTP Request Smuggling
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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