FKIE_CVE-2026-109821
Vulnerability from fkie_nvd - Published: 2026-10-30 09:17 - Updated: 2026-10-30 19:39
Severity
Summary
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.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"cpes": [
"cpe:2.3:a:elixir-lang:elixir:*:*:*:*:*:*:*:*"
],
"defaultStatus": "unaffected",
"modules": [
"\u0027Elixir.URI\u0027",
"\u0027Elixir.String.Chars.URI\u0027"
],
"packageName": "elixir",
"packageURL": "pkg:otp/elixir?repository_url=https:%2F%2Fgithub.com%2Felixir-lang%2Felixir\u0026vcs_url=git%2Bhttps:%2F%2Fgithub.com%2Felixir-lang%2Felixir.git",
"product": "elixir",
"programFiles": [
"lib/uri.ex"
],
"programRoutines": [
{
"name": "\u0027Elixir.URI\u0027:parse/1"
},
{
"name": "\u0027Elixir.URI\u0027:split_authority/1"
},
{
"name": "\u0027Elixir.URI\u0027:merge/2"
},
{
"name": "\u0027Elixir.URI\u0027:to_string/1"
},
{
"name": "\u0027Elixir.String.Chars.URI\u0027:to_string/1"
}
],
"repo": "https://github.com/elixir-lang/elixir",
"vendor": "elixir-lang",
"versions": [
{
"lessThan": "1.18.6",
"status": "affected",
"version": "0.5.0",
"versionType": "semver"
},
{
"lessThan": "1.19.7",
"status": "affected",
"version": "1.19.0-rc.0",
"versionType": "semver"
},
{
"lessThan": "1.20.5",
"status": "affected",
"version": "1.20.0-rc.0",
"versionType": "semver"
}
]
},
{
"collectionURL": "https://github.com",
"cpes": [
"cpe:2.3:a:elixir-lang:elixir:*:*:*:*:*:*:*:*"
],
"defaultStatus": "unaffected",
"modules": [
"\u0027Elixir.URI\u0027",
"\u0027Elixir.String.Chars.URI\u0027"
],
"packageName": "elixir-lang/elixir",
"packageURL": "pkg:github/elixir-lang/elixir",
"product": "elixir",
"programFiles": [
"lib/elixir/lib/uri.ex"
],
"programRoutines": [
{
"name": "\u0027Elixir.URI\u0027:parse/1"
},
{
"name": "\u0027Elixir.URI\u0027:split_authority/1"
},
{
"name": "\u0027Elixir.URI\u0027:merge/2"
},
{
"name": "\u0027Elixir.URI\u0027:to_string/1"
},
{
"name": "\u0027Elixir.String.Chars.URI\u0027:to_string/1"
}
],
"repo": "https://github.com/elixir-lang/elixir",
"vendor": "elixir-lang",
"versions": [
{
"changes": [
{
"at": "9a39d64a4473d02681c486bc70681c972479d32b",
"status": "unaffected"
},
{
"at": "b70f33a591b6ab8eb0fa4a7e00bac1c2ed4e0d58",
"status": "unaffected"
},
{
"at": "07d9abc3f3ac4c8d2ba8384bd102b6d6205b08b7",
"status": "unaffected"
},
{
"at": "d879b39d778fec2f475689573d5672720c4f2a21",
"status": "unaffected"
}
],
"lessThan": "*",
"status": "affected",
"version": "39801821eef2d06524e5ebf5a0e4b3c380ad23ae",
"versionType": "git"
}
]
}
],
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "Improper Validation of Specified Quantity in Input vulnerability in the Elixir standard library\u0027s URI module allows an attacker who supplies a URL to cause a denial of service through CPU exhaustion.\n\nURI.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.\n\nThis 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."
}
],
"id": "CVE-2026-109821",
"lastModified": "2026-10-30T19:39:14.897",
"metrics": {
"cvssMetricV40": [
{
"cvssData": {
"Automatable": "NOT_DEFINED",
"Recovery": "NOT_DEFINED",
"Safety": "NOT_DEFINED",
"attackComplexity": "LOW",
"attackRequirements": "PRESENT",
"attackVector": "NETWORK",
"availabilityRequirement": "NOT_DEFINED",
"baseScore": 6.3,
"baseSeverity": "MEDIUM",
"confidentialityRequirement": "NOT_DEFINED",
"exploitMaturity": "NOT_DEFINED",
"integrityRequirement": "NOT_DEFINED",
"modifiedAttackComplexity": "NOT_DEFINED",
"modifiedAttackRequirements": "NOT_DEFINED",
"modifiedAttackVector": "NOT_DEFINED",
"modifiedPrivilegesRequired": "NOT_DEFINED",
"modifiedSubAvailabilityImpact": "NOT_DEFINED",
"modifiedSubConfidentialityImpact": "NOT_DEFINED",
"modifiedSubIntegrityImpact": "NOT_DEFINED",
"modifiedUserInteraction": "NOT_DEFINED",
"modifiedVulnAvailabilityImpact": "NOT_DEFINED",
"modifiedVulnConfidentialityImpact": "NOT_DEFINED",
"modifiedVulnIntegrityImpact": "NOT_DEFINED",
"privilegesRequired": "NONE",
"providerUrgency": "NOT_DEFINED",
"subAvailabilityImpact": "NONE",
"subConfidentialityImpact": "NONE",
"subIntegrityImpact": "NONE",
"userInteraction": "NONE",
"valueDensity": "NOT_DEFINED",
"vectorString": "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",
"version": "4.0",
"vulnAvailabilityImpact": "LOW",
"vulnConfidentialityImpact": "NONE",
"vulnIntegrityImpact": "NONE",
"vulnerabilityResponseEffort": "NOT_DEFINED"
},
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-109821",
"options": [
{
"exploitation": "poc"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-10-30T16:52:15.736711Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-10-30T09:17:12.143",
"references": [
{
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"url": "https://cna.erlef.org/cves/CVE-2026-109821.html"
},
{
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"url": "https://github.com/elixir-lang/elixir/commit/07d9abc3f3ac4c8d2ba8384bd102b6d6205b08b7"
},
{
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"url": "https://github.com/elixir-lang/elixir/commit/39801821eef2d06524e5ebf5a0e4b3c380ad23ae"
},
{
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"url": "https://github.com/elixir-lang/elixir/commit/9a39d64a4473d02681c486bc70681c972479d32b"
},
{
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"url": "https://github.com/elixir-lang/elixir/commit/b70f33a591b6ab8eb0fa4a7e00bac1c2ed4e0d58"
},
{
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"url": "https://github.com/elixir-lang/elixir/commit/d879b39d778fec2f475689573d5672720c4f2a21"
},
{
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"url": "https://github.com/elixir-lang/elixir/security/advisories/GHSA-327h-97cv-59xg"
},
{
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"url": "https://github.com/erlang/otp/security/advisories/GHSA-8qw4-2chm-mvj2"
},
{
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"url": "https://osv.dev/vulnerability/EEF-CVE-2026-109821"
},
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"url": "https://github.com/elixir-lang/elixir/security/advisories/GHSA-327h-97cv-59xg"
}
],
"sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"vulnStatus": "Deferred",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-400"
},
{
"lang": "en",
"value": "CWE-1284"
}
],
"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
"type": "Secondary"
}
]
}
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