Input vulnerability · Improper Validation of Specified Quantity
Affects elixirSource GCVE Database
Not known to be exploited · CVSS 6.3 Medium.
Data as of 5 Nov 2026, 12:35 UTC
Thin evidence
One scorer or none| CNA (EEF) | CVSS 4.0 | 6.3 |
|---|---|---|
| CNA | CVSS 4.0 | 6.3 |
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 30 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 18.04 LTSelixirpkg:deb/ubuntu/elixir?arch=source&distro=bionicOther threats | Affected
| Fixed in– |
Ubuntu 16.04 LTSelixirpkg:deb/ubuntu/elixir?arch=source&distro=xenialOther threats | Affected
| Fixed in– |
Ubuntu 14.04 LTSelixirpkg:deb/ubuntu/elixir?arch=source&distro=trustyOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
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
- ubuntu.com/security/CVE-2026-109821 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-109821 (opens in a new tab)
- cna.erlef.org/cves/CVE-2026-109821.html (opens in a new tab)
- github.com/elixir-lang/elixir/commit/07d9abc3f3ac4c8d2ba8384bd102b6d6205b08b7 (opens in a new tab)
- github.com/elixir-lang/elixir/commit/39801821eef2d06524e5ebf5a0e4b3c380ad23ae (opens in a new tab)
- github.com/elixir-lang/elixir/commit/9a39d64a4473d02681c486bc70681c972479d32b (opens in a new tab)
- github.com/elixir-lang/elixir/commit/b70f33a591b6ab8eb0fa4a7e00bac1c2ed4e0d58 (opens in a new tab)
- github.com/elixir-lang/elixir/commit/d879b39d778fec2f475689573d5672720c4f2a21 (opens in a new tab)
- github.com/elixir-lang/elixir/security/advisories/GHSA-327h-97cv-59xg (opens in a new tab)
- github.com/erlang/otp/security/advisories/GHSA-8qw4-2chm-mvj2 (opens in a new tab)
- osv.dev/vulnerability/EEF-CVE-2026-109821 (opens in a new tab)