CVE-2026-109821

MEDIUMPre-NVD 6.36.3
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This medium-severity CVE scores 6.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5% (42nd percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
Trending — 4 sources updated this weekElevated

Also known asEUVD-2026-113757 (ENISA EUVD)Source: ENISA EUVD

6.3EG
EchelonGraph verdictPlan mitigationNo release containing the referenced fix is confirmed: check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 6.3Exploit: No code on recordExposed services: Not assessed

A fix is referenced (a reference tagged "Patch", often a source commit), but no release containing it is confirmed — find the release that contains it; until it is applied, mitigate (WAF / firewall / segmentation).

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 v3
6.3
EG Score
6.3MEDIUMmedium confidence
EG Risk
44
EG Risk 44/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity63% × 45%
Impact severity (EG Severity): CVSS 6.3 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule.
EPSS PROB
0.5%
EPSS %ILE
42nd
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (6.3): severity, escalated by confirmed exploitation. This CVE's 6.3 is its impact severity (EG Severity), not escalated.

EG Severity
6.3 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source · CVSS v3.0 or v3.1
EG Likelihood
0.5% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-30). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

October 30, 2026

Last Modified

October 30, 2026

Advisory Details (9)

Auto-updated Oct 30, 2026
🔬 Proof of concept available. Fix referenced — no release confirmed yet. Sources: github, github_commit.
GitHub commit

commit d879b39d778f (elixir-lang/elixir)

Fix landed in elixir-lang/elixir commit d879b39d778f — awaiting tagged release

https://github.com/elixir-lang/elixir/commit/d879b39d778fec2f475689573d5672720c4f2a21
GitHub commit

commit 07d9abc3f3ac (elixir-lang/elixir)

Fix landed in elixir-lang/elixir commit 07d9abc3f3ac — awaiting tagged release

https://github.com/elixir-lang/elixir/commit/07d9abc3f3ac4c8d2ba8384bd102b6d6205b08b7
GitHub commit

commit b70f33a591b6 (elixir-lang/elixir)

Fix landed in elixir-lang/elixir commit b70f33a591b6 — awaiting tagged release

https://github.com/elixir-lang/elixir/commit/b70f33a591b6ab8eb0fa4a7e00bac1c2ed4e0d58
GitHub commit

commit 9a39d64a4473 (elixir-lang/elixir)

Fix landed in elixir-lang/elixir commit 9a39d64a4473 — awaiting tagged release

https://github.com/elixir-lang/elixir/commit/9a39d64a4473d02681c486bc70681c972479d32b
GitHub commit

commit 39801821eef2 (elixir-lang/elixir)

Fix landed in elixir-lang/elixir commit 39801821eef2 — awaiting tagged release

https://github.com/elixir-lang/elixir/commit/39801821eef2d06524e5ebf5a0e4b3c380ad23ae
GitHub advisoryMentions a patch (unverified)

stdlib: Denial-of-Service enabled by Unbounded Integer Conversion · Advisory · erlang/otp · GitHub

https://github.com/erlang/otp/security/advisories/GHSA-8qw4-2chm-mvj2
Web page🟡 PoC Available

OSV - Open Source Vulnerabilities

https://osv.dev/vulnerability/EEF-CVE-2026-109821
Web page🟡 PoC Available

CVE-2026-109821

https://cna.erlef.org/cves/CVE-2026-109821.html
GitHub advisoryMentions a patch (unverified)🟡 PoC Available

Unbounded port parsing in URI.parse/1 enables CPU exhaustion denial of service · Advisory · elixir-lang/elixir · GitHub

https://github.com/elixir-lang/elixir/security/advisories/GHSA-327h-97cv-59xg

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 8× in last 7d / 8× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

  1. 2026-10-31 16:31 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  2. 2026-10-30 17:27 UTCEG score recompute
  3. 2026-10-30 17:00 UTCEG score recompute
  4. 2026-10-30 16:33 UTCEPSS rescoreEPSS 0.5% · 42nd percentile
  5. 2026-10-30 09:26 UTCEG score recompute
  6. 2026-10-30 09:02 UTCENISA EUVD ID recordedEUVD-2026-113757 · Source: ENISA EUVD
  7. 2026-10-30 09:00 UTCEG score recomputeFirst assessed: 6.3 MEDIUM
  8. 2026-10-30 08:59 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-109821?
CVE-2026-109821 is a medium-severity vulnerability; its CVE record was published on October 30, 2026. 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…
When was CVE-2026-109821 made public?
CVE-2026-109821 was made public on October 30, 2026: that is the date its CVE record's CNA, Erlang Ecosystem Foundation, gives for when the vulnerability was made public. The CVE record itself was published on October 30, 2026. EchelonGraph's copy of the record carries a last-modified date of October 30, 2026; the record at its source may have been updated since.
Is CVE-2026-109821 actively exploited?
CVE-2026-109821 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (42nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-109821?
CVE-2026-109821 has a CVSS base score of 6.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-109821?
A fix for CVE-2026-109821 is referenced (a reference tagged "Patch", often a source commit), but EchelonGraph has no release containing it on record. Check that reference and the vendor's advisory for a release that contains the fix and update to it; until then, restrict network exposure of the affected system or apply the vendor's mitigation.

Dependency Blast Radius

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