Mint HTTP/2 client buffers oversized frames up to 16 MiB before enforcing max_frame_size

Summary

CVECVE-2026-92103
StatePUBLISHED
AssignerEEF
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-28 12:17:41 UTC
Updated2026-09-30 16:19:23 UTC
DescriptionAllocation of Resources Without Limits or Throttling vulnerability in elixir-mint mint allows a malicious HTTP/2 server to make the client hold up to about 16 MiB per connection in frames it should reject, consuming client memory. Mint.HTTP2.Frame.decode_next/2 in lib/mint/http2/frame.ex compares a frame with the client's max_frame_size (16,384 bytes by default) only once the whole declared payload has arrived. Until then it returns :more, and Mint.HTTP2 keeps every received byte in the connection buffer. A server can declare a frame length of up to 16,777,215 bytes and withhold the last byte, keeping roughly 1,024 times the advertised limit buffered for as long as the connection stays open. The server has to send every byte the client buffers, so there is no amplification, and the buffer stops at the 24-bit frame length limit. This issue affects mint: from 0.1.0 before 1.10.2.

Risk And Classification

Primary CVSS: v4.0 6.3 MEDIUM from 6b3ad84c-e1a6-4bf7-a703-f496b71e49db

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

EPSS: 0.003010000 probability, percentile 0.205360000 (date 2026-09-29)

Problem Types: CWE-770 | CWE-770 CWE-770 Allocation of Resources Without Limits or Throttling


VersionSourceTypeScoreSeverityVector
4.06b3ad84c-e1a6-4bf7-a703-f496b71e49dbSecondary6.3MEDIUMCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/C...
4.0CNACVSS6.3MEDIUMCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
None
User Interaction
None
Confidentiality
None
Integrity
None
Availability
Low
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Elixir-mint Mint affected 0.1.0 1.10.2 semver Not specified
CNA Elixir-mint Mint affected 596ca4304504be68939c4929e0831557097962b8 * git Not specified

References

ReferenceSourceLinkTags
github.com/elixir-mint/mint/commit/44d7ce4755d0444ee415cbcca7ce4942382da4dd 6b3ad84c-e1a6-4bf7-a703-f496b71e49db github.com
github.com/elixir-mint/mint/security/advisories/GHSA-q95c-ccq6-j5j6 6b3ad84c-e1a6-4bf7-a703-f496b71e49db github.com
cna.erlef.org/cves/CVE-2026-92103.html 6b3ad84c-e1a6-4bf7-a703-f496b71e49db cna.erlef.org
github.com/elixir-mint/mint/commit/20252ca85065f4d1092aed9ee4ed21841a507dfe 6b3ad84c-e1a6-4bf7-a703-f496b71e49db github.com
osv.dev/vulnerability/EEF-CVE-2026-92103 6b3ad84c-e1a6-4bf7-a703-f496b71e49db osv.dev
github.com/elixir-mint/mint/commit/596ca4304504be68939c4929e0831557097962b8 6b3ad84c-e1a6-4bf7-a703-f496b71e49db github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: zx (en)

CNA: zx (en)

CNA: Andrea Leopardi (en)

CNA: Eric Meadows-Jönsson (en)

Additional Advisory Data

Workarounds

CNA: Connect to untrusted origins over HTTP/1 only, with protocols: [:http1] in Mint.HTTP.connect/4, which never runs the HTTP/2 frame decoder. Finch and Req pools use HTTP/1 only unless :http2 is added to their protocols option.

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