CVE-2026-31842Public exploitNetwork attack vector

Backend denial of service via case-sensitive chunk detection

Published Apr 7, 2026 · Updated Apr 7, 2026

HTTP request desynchronization in Tinyproxy 1.11.3 and earlier allows remote attackers to hang backend connections via crafted requests. The is_chunked_transfer() function in src/reqs.c compares Transfer-Encoding to "chunked" with case-sensitive strcmp(), treats "Chunked" as bodyless, and relays unread bytes. No authentication or special configuration is required; repeated incomplete chunk streams exhaust backend workers, while inspection deployments can pass bodies unparsed.

CVSS severity8.7
High
EPSS probability0.57%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

HTTP request desynchronization in Tinyproxy 1.11.3 and earlier allows remote attackers to hang backend connections via crafted requests. The is_chunked_transfer() function in src/reqs.c compares Transfer-Encoding to "chunked" with case-sensitive strcmp(), treats "Chunked" as bodyless, and relays unread bytes. No authentication or special configuration is required; repeated incomplete chunk streams exhaust backend workers, while inspection deployments can pass bodies unparsed.

The record

CVE
CVE-2026-31842
Published
Apr 7, 2026
Updated
Apr 7, 2026
Vendor
Tinyproxy
Product
Tinyproxy
Classifications
CWE-444, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 7, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 7, 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=0 <=1.11.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Tinyproxy · Tinyproxyversion=0 <=1.11.3

Published CVSS scores

7.8TuranSecAV:N/AC:L/Au:N/C:N/I:N/A:C
7.5TuranSecCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
8.7TuranSecCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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 exploitPublished

Weakness, pattern, technique

CWE-444Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
T1499.003Application Exhaustion Flood

Public exploit references

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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