CVE-2026-22776Public exploitNetwork attack vector

Server crash via unbounded request decompression

Published Jan 12, 2026 · Updated Jan 12, 2026

Resource exhaustion in Yuji Hirose cpp-httplib before 0.30.1 allows remote attackers to crash HTTP servers with compressed request bodies. The Server::read_content callback checks the compressed request size against payload_max_length_, then appends decompressed chunks without enforcing that limit. The host server must enable a supported decompressor and accept compressed request bodies; exploitation exhausts memory and shuts down the server without disclosing or modifying data.

CVSS severity8.7
High
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in Yuji Hirose cpp-httplib before 0.30.1 allows remote attackers to crash HTTP servers with compressed request bodies. The Server::read_content callback checks the compressed request size against payload_max_length_, then appends decompressed chunks without enforcing that limit. The host server must enable a supported decompressor and accept compressed request bodies; exploitation exhausts memory and shuts down the server without disclosing or modifying data.

The record

CVE
CVE-2026-22776
Published
Jan 12, 2026
Updated
Jan 12, 2026
Vendor
Yuji Hirose
Product
cpp-httplib
Classifications
CWE-400, CWE-409, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 12, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 12, 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=< 0.30.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Yuji Hirose · cpp-httplibversion=< 0.30.1

Published CVSS scores

8.7GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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-400Uncontrolled Resource Consumption
CWE-409Improper Handling of Highly Compressed Data (Data Amplification)
T1499.004Endpoint Denial of Service: Application or System Exploitation

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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