# CVE-2026-48593: Unbounded range expansion in cron describe causes memory exhaustion in oban_web

> An attacker can cause memory exhaustion and crash the server by submitting malicious cron expressions to the Oban Web dashboard.

- **Severity:** Medium 5.9 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 26 May 2026
- **Updated:** 27 May 2026
- **Also known as:** EEF-CVE-2026-48593, GHSA-6xh2-93p9-vqh4

## What is CVE-2026-48593?

CVE-2026-48593 is a medium-severity denial of service vulnerability in oban-bg oban_web, published on 26 May 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

Uncontrolled Resource Consumption vulnerability in oban-bg oban_web ('Elixir.Oban.Web.CronExpr' modules) allows memory exhaustion via unbounded cron range expansion.

An attacker with access to schedule cron jobs can submit a malicious cron expression such as "0 0 1-100000000 * *". When a user with dashboard access views the cron job list, 'Elixir.Oban.Web.CronExpr':describe/1 is called to render the expression. parse_range/1 parses both range endpoints via Integer.parse/1 with no bounds check, and the downstream helpers expand_dom_parts/1 and expand_dow_parts/1 materialise the range eagerly via Enum.to_list/1, causing allocation of ~2.4 GB and stalling or crashing the BEAM node. A sibling helper extract_dom_values already validates range bounds, but the expansion helpers do not.

This issue affects oban_web: from 2.12.0 before 2.12.5.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2026-48593?

3 open source packages ship an affected version, including oban_web.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `oban_web` | Hex | From 2.12.0 | 2.12.5 |
| `oban_web` | Hex | From 2.12.0 | 2.12.5 |
| `oban_web` | Hex | From 2.12.0 | 2.12.5 |

## How do I fix CVE-2026-48593?

Upgrade oban_web to 2.12.5 or later.

## Is CVE-2026-48593 being exploited?

There is no known exploitation of CVE-2026-48593 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-48593 and fix it if it is affected.

What it is: CVE-2026-48593 is a medium-severity denial of service vulnerability in oban-bg oban_web, published on 26 May 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-48593 in the wild and no public exploit code.

Affected packages and fixed versions:
- oban_web (Hex): affected from 2.12.0; fixed in 2.12.5
- oban_web (Hex): affected from 2.12.0; fixed in 2.12.5
- oban_web (Hex): affected from 2.12.0; fixed in 2.12.5

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-2026-48593/ (Markdown: https://insights.sbomify.com/CVE-2026-48593/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-48593
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-48593
- OSV: https://osv.dev/vulnerability/CVE-2026-48593

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-48593/
Summaries are generated and may contain mistakes; the official description above is the record.