# CVE-2026-59696: uri_string does not bound the port component of a URI before integer conversion

> Remote attackers can cause denial of service by supplying URIs with excessively long port numbers, forcing expensive integer conversions in Erlang OTP applications.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 1 Sep 2026
- **Updated:** 8 Sep 2026
- **Also known as:** AZL-98457, DEBIAN-CVE-2026-59696, EEF-CVE-2026-59696, GHSA-8qw4-2chm-mvj2, UBUNTU-CVE-2026-59696

## What is CVE-2026-59696?

CVE-2026-59696 is a medium-severity denial of service vulnerability in Erlang OTP, published on 1 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Improper Validation of Specified Quantity in Input vulnerability in Erlang/OTP stdlib allows a remote attacker to degrade availability by supplying a URI whose port component is a very long run of digits.

uri_string:get_port/1 passes the port substring to binary_to_integer/1 with no length bound, catching only error:badarg, so a syntactically valid port of up to roughly 1.26 million digits converts successfully and costs the calling process hundreds of milliseconds of arbitrary-precision arithmetic. The conversion is reached from every authority-parsing path in uri_string:parse/1, including the host, registered-name, and IPv4 and IPv6 forms. parse/1 is the documented interface for parsing URIs, so any application that parses an attacker-supplied URI is exposed without further configuration. The conversion function is documented to accept integers of any size, so bounding the input is the caller's responsibility.

This issue affects OTP from OTP 21.0 before OTP 27.3.4.17, from OTP 28.0 before OTP 28.5.0.6, and from OTP 29.0 before OTP 29.0.6, corresponding to stdlib from 3.5 before 6.2.2.5, from 7.0 before 7.3.0.2, and from 8.0 before 8.0.4.

Weakness: CWE-1284 (Improper Validation of Specified Quantity in Input)

## Which versions are affected by CVE-2026-59696?


## How do I fix CVE-2026-59696?

Upgrade to a fixed version.

## Is CVE-2026-59696 being exploited?

There is no known exploitation of CVE-2026-59696 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-59696 and fix it if it is affected.

What it is: CVE-2026-59696 is a medium-severity denial of service vulnerability in Erlang OTP, published on 1 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-59696 in the wild and no public exploit code.

Affected product: Erlang OTP. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-59696/ (Markdown: https://insights.sbomify.com/CVE-2026-59696/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-59696
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-59696
- OSV: https://osv.dev/vulnerability/CVE-2026-59696

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-59696/
Summaries are generated and may contain mistakes; the official description above is the record.