Unbounded buffer accumulation in multipart header parsing causes denial of service in plug

Summary

CVE	CVE-2026-8468
State	PUBLISHED
Assigner	EEF
Source Priority	CVE Program / NVD first with legacy fallback
Published	2026-05-14 11:16:18 UTC
Updated	2026-05-14 17:07:07 UTC
Description	Allocation of Resources Without Limits or Throttling vulnerability in plug_project plug allows denial of service via unbounded buffer accumulation in multipart header parsing. 'Elixir.Plug.Conn':read_part_headers/2 in lib/plug/conn.ex does not obey its :length parameter. There is no upper bound on the size of the accumulated buffer. By contrast, the sibling function read_part_body has an explicit byte_size(acc) > length guard that stops accumulation once a limit is reached. No such guard exists in read_part_headers. An unauthenticated remote attacker can exhaust server memory by sending a crafted multipart/form-data request, causing a denial of service. This issue affects plug from 1.4.0 before 1.15.4, 1.16.3, 1.17.1, 1.18.2, and 1.19.2.

Risk And Classification

Primary CVSS: v4.0 8.2 HIGH from 6b3ad84c-e1a6-4bf7-a703-f496b71e49db

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/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: 0.002690000 probability, percentile 0.503260000 (date 2026-05-25)

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

Version	Source	Type	Score	Severity	Vector
4.0	6b3ad84c-e1a6-4bf7-a703-f496b71e49db	Secondary	8.2	HIGH	`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/C...`
4.0	CNA	CVSS	8.2	HIGH	`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/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

High

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:H/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

Source	Vendor	Product	Version	Platforms
CNA	Elixir-plug	Plug	affected 1.4.0 1.15.4 semver	Not specified
CNA	Elixir-plug	Plug	affected 1.16.0 1.16.3 semver	Not specified
CNA	Elixir-plug	Plug	affected 1.17.0 1.17.1 semver	Not specified
CNA	Elixir-plug	Plug	affected 1.18.0 1.18.2 semver	Not specified
CNA	Elixir-plug	Plug	affected 1.19.0 1.19.2 semver	Not specified
CNA	Elixir-plug	Plug	affected c52b2f32c90bccd718202bafccb5f95594e30183 * git	Not specified

References

Reference	Source	Link	Tags
github.com/elixir-plug/plug/commit/33858427c7f2737d560a2e40a0c9a9270d77d1d7	6b3ad84c-e1a6-4bf7-a703-f496b71e49db	github.com
osv.dev/vulnerability/EEF-CVE-2026-8468	6b3ad84c-e1a6-4bf7-a703-f496b71e49db	osv.dev
github.com/elixir-plug/plug/commit/df812a1527bae9e941965e897308a2b8bbf83a94	6b3ad84c-e1a6-4bf7-a703-f496b71e49db	github.com
github.com/elixir-plug/plug/security/advisories/GHSA-468c-vq7p-gh64	6b3ad84c-e1a6-4bf7-a703-f496b71e49db	github.com
cna.erlef.org/cves/CVE-2026-8466.html	6b3ad84c-e1a6-4bf7-a703-f496b71e49db	cna.erlef.org
cna.erlef.org/cves/CVE-2026-8468.html	6b3ad84c-e1a6-4bf7-a703-f496b71e49db	cna.erlef.org
github.com/elixir-plug/plug/commit/aa69c5ece99c40ded88b8c6581ecc86664b0b734	6b3ad84c-e1a6-4bf7-a703-f496b71e49db	github.com
github.com/elixir-plug/plug/commit/d5dfffe25e975585227b1b85d247b0d14164bc45	6b3ad84c-e1a6-4bf7-a703-f496b71e49db	github.com
github.com/elixir-plug/plug/commit/2cb7958d33030aa826b0c7404375844d4593d43a	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: José Valim (en)

CNA: Jonatan Männchen (en)

There are currently no legacy QID mappings associated with this CVE.