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CVE

CVE-2026-34516

AIOHTTP has a Multipart Header Size Bypass
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CVE

CVE-2026-34516

AIOHTTP has a Multipart Header Size Bypass

Summary

A response with an excessive number of multipart headers may be allowed to use more memory than intended, potentially allowing a DoS vulnerability.

Impact

Multipart headers were not subject to the same size restrictions in place for normal headers, potentially allowing substantially more data to be loaded into memory than intended. However, other restrictions in place limit the impact of this vulnerability.

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Patch: https://github.com/aio-libs/aiohttp/commit/8a74257b3804c9aac0bf644af93070f68f6c5a6f

Package Versions Affected

Package Version
patch Availability
No items found.

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CVSS Version

Severity
Base Score
CVSS Version
Score Vector
C
H
U
6.6
-
4.0
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/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
C
H
U
0
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
C
H
U
7.5
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Related Resources

No items found.

References

https://github.com/aio-libs/aiohttp/security/advisories/GHSA-m5qp-6w8w-w647, https://nvd.nist.gov/vuln/detail/CVE-2026-34516, https://github.com/aio-libs/aiohttp/commit/8a74257b3804c9aac0bf644af93070f68f6c5a6f, https://github.com/aio-libs/aiohttp, https://github.com/aio-libs/aiohttp/releases/tag/v3.13.4

Severity

7.5

CVSS Score
0
10

Basic Information

Ecosystem
Base CVSS
7.5
EPSS Probability
0.0002%
EPSS Percentile
0.0588%
Introduced Version
0,3.5.0a1,0.15.0
Fix Available
3.13.4,2.11.2-r5,3.2.1-r0,2.11.2-r3,2025.12.4-r3,2026.2.1-r3,24.6.1-r33,3.2.517-r0,2026.3.0-r3,1.6.0-r1,1.5.0.1-r1,0.51.0-r2,0.17.0-r2,2.16.0-r4,1.82.3.0-r3,2.5.0-r10,2.5.0-r2,0.8.12-r3,0.27.1-r2,3.3.7-r10,25.9.0_git20260318-r1,25.11-r3

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