CVE-2026-34525 | BDVDB-2026-324220 Detail

aio-libsaiohttp

Description#

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, multiple Host headers were allowed in aiohttp. This issue has been patched in version 3.13.4.

Impact#

Per CVSS v4.0: confidentiality impact none, integrity impact low, availability impact none. Attack vector: network.

Weaknesses#

CWE-20 Improper Input Validation
CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

References#

Exploit#

No public exploit known

History#

Version 12026-04-01Record published in the CVE List.
Version 22026-06-23Most recent update recorded in the CVE List.

Published

Published: 2026-04-01
Last modified: 2026-06-23

Vendor information

Vendor: aio-libs
Product: aiohttp

All aio-libs vulnerabilities

Score

6.3 Medium

EPSS

less than 1%, Very Low

Estimated chance of exploitation in the next 30 days. EPSS percentile: 22.8.

KEV

Not listed in the CISA Known Exploited Vulnerabilities catalog.

Impact

Improper Input Validation

Action

No specific action is recorded in the source data. Check the references for vendor guidance.

Affected Systems

Vulnerable
< 3.13.4
Fixed
Not stated

Scoring System

CVSS v4.0

6.3 Medium

CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N

Metric breakdown
Attack Vector	Network
Attack Complexity	High
Attack Requirements	Present
Privileges Required	None
User Interaction	None
Vulnerable System Confidentiality	None
Vulnerable System Integrity	Low
Vulnerable System Availability	None
Subsequent System Confidentiality	Low
Subsequent System Integrity	Low
Subsequent System Availability	None

CVSS v3.1

Not available

CVSS v3.0

Not available

CVSS v2

Not available

Source: CVE List v5 (record); CISA KEV (kev, action); FIRST EPSS (epss).