CVE-2026-34517
published 2026-04-01CVE-2026-34517: AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, for some multipart form fields, aiohttp read the…
PriorityP429medium5.3CVSS 3.1
AVNACLPRNUINSUCNINAL
EPSS
0.38%
31.0th percentile
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, for some multipart form fields, aiohttp read the entire field into memory before checking client_max_size. This issue has been patched in version 3.13.4.
Affected
4 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| aio-libs | aiohttp | < 3.13.4 | 3.13.4 |
| aiohttp | aiohttp | < 3.13.4 | 3.13.4 |
| aiohttp | aiohttp | >= 0 < 3.13.4 | 3.13.4 |
| debian | python-aiohttp | — | — |
CVSS provenance
nvdv3.15.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
nvdv4.02.7LOWCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
osv2.7LOW
vendor_debian2.7LOW
vendor_redhat2.7LOW
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OSV
AIOHTTP has late size enforcement for non-file multipart fields causes memory DoS
osv·2026-04-01
CVE-2026-34517 [LOW] AIOHTTP has late size enforcement for non-file multipart fields causes memory DoS
AIOHTTP has late size enforcement for non-file multipart fields causes memory DoS
### Summary
For some multipart form fields, aiohttp read the entire field into memory before checking client_max_size.
### Impact
If an application uses `Request.post()` an attacker can send a specially crafted multipart request to force significant temporary memory allocation even when the request is ultimately rejected.
Patch: https://github.com/aio-libs/aiohttp/commit/cbb774f38330563422ca0c413a71021d7b944145
GHSA
AIOHTTP has late size enforcement for non-file multipart fields causes memory DoS
ghsa·2026-04-01
CVE-2026-34517 [LOW] CWE-770 AIOHTTP has late size enforcement for non-file multipart fields causes memory DoS
AIOHTTP has late size enforcement for non-file multipart fields causes memory DoS
### Summary
For some multipart form fields, aiohttp read the entire field into memory before checking client_max_size.
### Impact
If an application uses `Request.post()` an attacker can send a specially crafted multipart request to force significant temporary memory allocation even when the request is ultimately rejected.
Patch: https://github.com/aio-libs/aiohttp/commit/cbb774f38330563422ca0c413a71021d7b944145
OSV
CVE-2026-34517: AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python
osv·2026-04-01·CVSS 2.7
CVE-2026-34517 [LOW] CVE-2026-34517: AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, for some multipart form fields, aiohttp read the entire field into memory before checking client_max_size. This issue has been patched in version 3.13.4.
Red Hat
aiohttp: AIOHTTP: Denial of Service via large multipart form fields
vendor_redhat·2026-04-01·CVSS 2.7
CVE-2026-34517 [LOW] CWE-770 aiohttp: AIOHTTP: Denial of Service via large multipart form fields
aiohttp: AIOHTTP: Denial of Service via large multipart form fields
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, for some multipart form fields, aiohttp read the entire field into memory before checking client_max_size. This issue has been patched in version 3.13.4.
A flaw was found in AIOHTTP, an asynchronous HTTP client/server framework for Python. A remote attacker could exploit this vulnerability by sending a specially crafted multipart form field. The framework would read the entire field into memory before enforcing size limits, potentially leading to excessive memory consumption and a Denial of Service (DoS) for the affected system.
Mitigation: Mitigation for this issue is either not available or the currently available
Debian
CVE-2026-34517: python-aiohttp - AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. ...
vendor_debian·2026·CVSS 2.7
CVE-2026-34517 [LOW] CVE-2026-34517: python-aiohttp - AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. ...
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, for some multipart form fields, aiohttp read the entire field into memory before checking client_max_size. This issue has been patched in version 3.13.4.
Scope: local
bookworm: open
bullseye: open
forky: open
sid: open
trixie: open
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-34517 aiohttp: AIOHTTP: Denial of Service via large multipart form fields
bugzilla·2026-04-01·CVSS 2.7
CVE-2026-34517 [LOW] CVE-2026-34517 aiohttp: AIOHTTP: Denial of Service via large multipart form fields
CVE-2026-34517 aiohttp: AIOHTTP: Denial of Service via large multipart form fields
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, for some multipart form fields, aiohttp read the entire field into memory before checking client_max_size. This issue has been patched in version 3.13.4.
Wiz
CVE-2026-34517 Impact, Exploitability, and Mitigation Steps | Wiz
blogs_wiz·CVSS 2.7
CVE-2026-34517 [LOW] CVE-2026-34517 Impact, Exploitability, and Mitigation Steps | Wiz
## CVE-2026-34517 :
Wolfi vulnerability analysis and mitigation
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, for some multipart form fields, aiohttp read the entire field into memory before checking client_max_size. This issue has been patched in version 3.13.4.
Source : NVD
## 2.7
Score
Published April 1, 2026
Severity LOW
CNA Score 2.7
Affected Technologies
Wolfi
Chainguard
Has Public Exploit No
Has CISA KEV Exploit No
CISA KEV Release Date N/A
CISA KEV Due Date N/A
Exploitation Probability Percentile (EPSS) 16.4
Exploitation Probability (EPSS) 0.1
Affected packages and libraries
datahub-ingestion-fips
keep
Sources
NVD
Chainguard Has Fix Added at: Apr 02, 2026
Debian 11, 12, 13, 14 No Fix Added at: Apr
2026-04-01
Published