CVE-2024-30251 | Denial of service when trying to parse malformed POST requests in aiohttp

aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. In affected versions an attacker can send a specially crafted POST (multipart/form-data) request. When the aiohttp server processes it, the server will enter an infinite loop and be unable to process any further requests. An attacker can stop the application from serving requests after sending a single request. This issue has been addressed in version 3.9.4. Users are advised to upgrade. Users unable to upgrade may manually apply a patch to their systems. Please see the linked GHSA for instructions.

Published: 2024-05-02 Last update: 2025-11-03 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2024-30251 is rated Moderate Risk (50/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.34%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2024-30251

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-28 0.25% 0.34% +0.09%
2 2026-05-23 0.33% 0.25% -0.09%
3 2026-04-19 — 0.33% —

Full EPSS history (20 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2024-30251

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2024-30251

GitHub Security Advisory for CVE-2024-30251

GHSA-5m98-qgg9-wh84 · Severity: high · Ecosystem: pip — aiohttp vulnerable to Denial of Service when trying to parse malformed POST requests

OS Trackers for CVE-2024-30251

vendor priority summary link
debian not yet assigned CVE-2024-30251 not yet assigned priority: Debian including 1 source packages (python-aiohttp), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2024-30251
gentoo normal CVE-2024-30251: 1 GLSA(s) (202408-11), 1 atom(s) (dev-python/aiohttp); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2024-30251
redhat high — https://access.redhat.com/security/cve/CVE-2024-30251
suse high — https://www.suse.com/security/cve/CVE-2024-30251/
ubuntu medium CVE-2024-30251 medium priority: Ubuntu including 1 source packages (python-aiohttp), 10 status rows across 10 suites (bionic, focal, jammy, mantic, noble, oracular, plucky, questing, upstream, xenial): not-affected 5, released 4, ignored 1. https://ubuntu.com/security/CVE-2024-30251

Affected software / configurations for CVE-2024-30251

Vendor Product Version Raw CPE
aiohttp aiohttp < 3.9.4 cpe:2.3:a:aiohttp:aiohttp:*:*:*:*:*:*:*:*

References for CVE-2024-30251

cvelogic Threat Intelligence