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.
- 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
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
Which versions are affected by CVE-2026-48593?
3 open source packages ship an affected version, including oban_web.
| Package | 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.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-48593 being exploited?
There is no known exploitation of CVE-2026-48593 in the wild and no public exploit code.
Sources
Also known as EEF-CVE-2026-48593, GHSA-6xh2-93p9-vqh4.