CVE-2025-69228Network attack vector

Memory exhaustion via per-field multipart size reset

Published Jan 5, 2026 · Updated Jan 5, 2026

Resource exhaustion in aiohttp before 3.13.3 allows remote attackers to freeze servers via multipart requests handled by Request.post(). The Request.post() multipart loop resets its size counter for every field, so each part can remain below client_max_size while the combined form grows without limit. Exploitation requires an application handler that calls Request.post(); a crafted multi-field upload then exhausts process memory and interrupts the service.

CVSS severity7.5
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 aiohttp before 3.13.3 allows remote attackers to freeze servers via multipart requests handled by Request.post(). The Request.post() multipart loop resets its size counter for every field, so each part can remain below client_max_size while the combined form grows without limit. Exploitation requires an application handler that calls Request.post(); a crafted multi-field upload then exhausts process memory and interrupts the service.

The record

CVE
CVE-2025-69228
Published
Jan 5, 2026
Updated
Jan 5, 2026
Vendor
aio-libs
Product
aiohttp
Classifications
CWE-770, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 5, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 5, 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=< 3.13.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

aio-libs · aiohttpversion=< 3.13.3

Published CVSS scores

6.6GitHub, 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/E:U
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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
T1499.003Endpoint Denial of Service: Application Exhaustion Flood

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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