CVE-2026-22815Network attack vector

Memory exhaustion via unbounded HTTP trailer accumulation

Published Apr 1, 2026 · Updated Apr 1, 2026

Resource exhaustion in aiohttp before 3.13.4 allows remote attackers to exhaust application memory with crafted HTTP messages. Its HTTP request and response parsers retain attacker-controlled header and trailer fields without enforcing a bounded count. The server path requires direct receipt of a crafted request, while client exposure requires connecting to an attacker-controlled responder.

CVSS severity6.9
Medium
EPSS probability0.44%
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 3.13.4 allows remote attackers to exhaust application memory with crafted HTTP messages. Its HTTP request and response parsers retain attacker-controlled header and trailer fields without enforcing a bounded count. The server path requires direct receipt of a crafted request, while client exposure requires connecting to an attacker-controlled responder.

The record

CVE
CVE-2026-22815
Published
Apr 1, 2026
Updated
Apr 1, 2026
Vendor
aio-libs
Product
aiohttp
Classifications
CWE-770, CWE-400, T1499.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 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=< 3.13.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

aio-libs · aiohttpversion=< 3.13.4

Published CVSS scores

7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
6.9GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/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.

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

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-770Allocation of Resources Without Limits or Throttling
CWE-400Uncontrolled Resource Consumption
T1499.002Service 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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