CVE-2026-109821

Unbounded port parsing in URI.parse/1 enables CPU exhaustion denial of service in Elixir

CVSS score

6.3

EPSS probability

—

Risk score

0.6

Published

2 h ago

Overview Public Exploits (0)Newsroom Vulnerability Timeline

Official patch verified

Etkilenen ürün ve sürüm için yayımlanan güvenlik güncellemesini uygulayın.

Impact on My Inventory

Only the personal products you have added to your account are assessed; an organisation's inventory does not appear here.

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Vulnerability description

DayBreach AI Explanation

Verified against sources

CPU Exhaustion in URI.parse/1 within Elixir Standard Library

Sources read

Source agreement

Tam uyum

Evidence confidence

%55

Short explanation

CVE-2026-109821 is an improper input validation vulnerability in the URI module of the Elixir standard library, allowing a denial of service through CPU exhaustion via unconstrained port parsing.

Why does it matter?

This vulnerability enables attackers to exhaust application resources and cause a denial of service by supplying maliciously crafted URLs.

What should be done?

Follow the vendor advisory and patch references
Update the affected Elixir versions

Chain of evidence and sources2 verified claims

URI.parse/1 fonksiyonu bağlantı noktası uzunluğunu sınırlamaz ve CPU tükenmesine yol açabilir.

S0 · daybreach-canonical S1 · cvelist

Güvenlik açığı belirli Elixir sürümlerini etkilemektedir ve yama başvuruları mevcuttur.

S0 · daybreach-canonical S1 · cvelist

Show the technical text from the sources

Improper Validation of Specified Quantity in Input vulnerability in the Elixir standard library's URI module allows an attacker who supplies a URL to cause a denial of service through CPU exhaustion. URI.parse/1 converts the port component with String.to_integer/1 in split_authority/1 (lib/elixir/lib/uri.ex) without bounding its length, so a port of up to 1,262,592 decimal digits produces a bignum of that size and a longer one raises SystemLimitError. Rendering the parsed URI back to text (URI.to_string/1, inspect/1, logging, error formatting) converts the bignum with :erlang.integer_to_binary/1, which is quadratic on Erlang/OTP 27, 28 and 29.0: a 400,000-digit port renders in about 2.6 seconds and a 1 MB port in about 18 seconds. Ports above 65535 are also accepted. This issue affects elixir: from 0.5.0 before 1.18.6, from 1.19.0-rc.0 before 1.19.7, and from 1.20.0-rc.0 before 1.20.5.

CVSS vector: 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

CWE: CWE-1284, CWE-400

This explanation was compiled automatically from the source records. Scores, active exploitation, patch and exploit status come straight from the sources.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-109821 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

ID	VENDOR	PRODUCT	ACTION
1	elixir-lang	elixir	View
2	elixir-lang	elixir	View

Total affected vendors: 1|Products: 2

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCORE	VERSION	SEVERITY	VECTOR	SOURCE
6.3	CVSS V40	MEDIUM	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	NVD
6.3	CVSS V4_0	MEDIUM	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	CVE CNA

Patch and Remediation Guide

Solution & Remediation Advisory

Patch verified

8 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

cvelist

Fix commit 9a39d64 in elixir-lang/elixir

Open source

cvelist

Fix commit b70f33a in elixir-lang/elixir

Open source

cvelist

Fix commit 07d9abc in elixir-lang/elixir

Open source

cvelist

Fix commit d879b39 in elixir-lang/elixir

Open source

reference

Fix commit 9a39d64 in elixir-lang/elixir

Open source

reference

Fix commit b70f33a in elixir-lang/elixir

Open source

reference

Fix commit 07d9abc in elixir-lang/elixir

Open source

reference

Fix commit d879b39 in elixir-lang/elixir

Open source

Confirm the affected product and version against the source evidence above.

Restrict access to internet-facing services and apply network segmentation.

Apply the official update named in the evidence only to the matching product and version.

Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-109821 is associated with the following CWEs:

CWE-1284: Common Weakness Enumeration Entry CWE-1284 CWE-400: Common Weakness Enumeration Entry CWE-400

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-109821 weaknesses.

CAPEC-66: SQL Injection CAPEC-126: Path Traversal CAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureAğ üzerinden

PermissionsGerekmiyor

UserGerekmiyor

Official Sources and Advisories

Unbounded port parsing in URI.parse/1 enables CPU exhaustion denial of servicevendor-advisory EEF CNA record for CVE-2026-109821vendor-advisory OSV record EEF-CVE-2026-109821vendor-advisory Erlang/OTP advisory for the same issue in uri_stringvendor-advisory Introducing commit 3980182 in elixir-lang/elixirvendor-advisory Fix commit 9a39d64 in elixir-lang/elixirpatch Fix commit b70f33a in elixir-lang/elixirpatch Fix commit 07d9abc in elixir-lang/elixirpatch Fix commit d879b39 in elixir-lang/elixirpatch

CVSS Vector Radar Chart

6.3 / 10

Vulnerability Scoring Details

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

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone required

User InteractionNone required

Confidentiality (Gizlilik)Low

Integrity (Bütünlük)None

Availability (Erişilebilirlik)Low

Yama doğrulandı

8 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

Follow the vendor

elixir-lang

Weakness Type (CWE & CAPEC)

CWE-1284 CWE-400

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Unbounded port parsing in URI.parse/1 enables CPU exhaustion denial of service in Elixir

Impact on My Inventory

Vulnerability description

DayBreach AI Explanation

Short explanation

What should be done?

IMPACT: Affected Products and Software

Affected Products

RED HAT CSAF/VEX: Product Impact Check

SCORING: CVSS from Multiple Sources

CVSS Scores

Patch and Remediation Guide

Solution & Remediation Advisory

Public exploit and active exploitation status

Verified exploit intelligence

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

Common Attack Pattern Enumeration and Classification (CAPEC)

Attack Vector and Accessibility

Official Sources and Advisories

CVSS Vector Radar Chart

Vulnerability Scoring Details

Weakness Type (CWE & CAPEC)

Similar Vulnerabilities

Get this vulnerability through the API

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