Vulnerability-Lookup

GHSA-6XH2-93P9-VQH4

Vulnerability from github – Published: 2026-06-30 18:32 – Updated: 2026-06-30 18:32

Summary

oban_web: Unbounded range expansion in cron describe causes memory exhaustion

Details

Summary

oban_web 2.12.0 introduced a cron expression parser that expands --separated ranges without validating the endpoints. An attacker with access to schedule cron jobs can submit a malicious expression; when any user with dashboard access views the cron job list, Oban.Web.CronExpr.describe/1 is called to render it, triggering allocation of gigabytes of memory and stalling or crashing the BEAM node.

Details

1. Scheduling: The attacker submits a cron job with a malicious expression such as "0 0 1-100000000 * *". No special privilege is required beyond the ability to schedule cron jobs.

2. Parsing: When the cron list is rendered in the dashboard, describe/1 calls parse_range/1 in lib/oban/web/cron_expr.ex, which calls Integer.parse/1 on both endpoints of the range with no bounds check, returning {:range, start_val, end_val} for any integers.

3. Eager expansion: expand_dom_parts/1 and expand_dow_parts/1 materialise the range via Enum.to_list(start_val..end_val). The input above produces ~100 million integers (~2.4 GB). A sibling helper extract_dom_values already validates range bounds, but the expansion helpers do not.

PoC

Schedule a cron job with expression "0 0 1-100000000 * *" (or any expression with an out-of-domain range).
Have any user with Oban.Web dashboard access navigate to the cron job list.
The dashboard calls describe/1 to render the expression, exhausting BEAM memory and crashing the node.

Impact

CVSS 4.0 score 5.9 (Medium). Affects oban_web >= 2.12.0. Requires the ability to schedule a cron job and a dashboard user to view the cron list; no further privileges are needed.

References

Introduction commit: https://github.com/oban-bg/oban_web/commit/a97c7960bb389b05aaab4cf8042985f02ceddc24
Patch commit: https://github.com/oban-bg/oban_web/commit/9998b7e284e02fdd4645dd6231760038e63b584d

Severity

5.9 (Medium)


                  
                    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

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Hex",
        "name": "oban_web"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.12.0"
            },
            {
              "fixed": "2.12.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-48593"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-400"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-30T18:32:49Z",
    "nvd_published_at": "2026-05-26T21:16:41Z",
    "severity": "MODERATE"
  },
  "details": "### Summary\n\n`oban_web` 2.12.0 introduced a cron expression parser that expands `-`-separated ranges without validating the endpoints. An attacker with access to schedule cron jobs can submit a malicious expression; when any user with dashboard access views the cron job list, `Oban.Web.CronExpr.describe/1` is called to render it, triggering allocation of gigabytes of memory and stalling or crashing the BEAM node.\n\n### Details\n\n**1. Scheduling:** The attacker submits a cron job with a malicious expression such as `\"0 0 1-100000000 * *\"`. No special privilege is required beyond the ability to schedule cron jobs.\n\n**2. Parsing:** When the cron list is rendered in the dashboard, `describe/1` calls `parse_range/1` in `lib/oban/web/cron_expr.ex`, which calls `Integer.parse/1` on both endpoints of the range with no bounds check, returning `{:range, start_val, end_val}` for any integers.\n\n**3. Eager expansion:** `expand_dom_parts/1` and `expand_dow_parts/1` materialise the range via `Enum.to_list(start_val..end_val)`. The input above produces ~100 million integers (~2.4 GB). A sibling helper `extract_dom_values` already validates range bounds, but the expansion helpers do not.\n\n### PoC\n\n1. Schedule a cron job with expression `\"0 0 1-100000000 * *\"` (or any expression with an out-of-domain range).\n2. Have any user with Oban.Web dashboard access navigate to the cron job list.\n3. The dashboard calls `describe/1` to render the expression, exhausting BEAM memory and crashing the node.\n\n### Impact\n\nCVSS 4.0 score 5.9 (Medium). Affects `oban_web` \u003e= 2.12.0. Requires the ability to schedule a cron job and a dashboard user to view the cron list; no further privileges are needed.\n\n### References\n\n* Introduction commit: https://github.com/oban-bg/oban_web/commit/a97c7960bb389b05aaab4cf8042985f02ceddc24\n* Patch commit: https://github.com/oban-bg/oban_web/commit/9998b7e284e02fdd4645dd6231760038e63b584d",
  "id": "GHSA-6xh2-93p9-vqh4",
  "modified": "2026-06-30T18:32:49Z",
  "published": "2026-06-30T18:32:49Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/oban-bg/oban_web/security/advisories/GHSA-6xh2-93p9-vqh4"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-48593"
    },
    {
      "type": "WEB",
      "url": "https://github.com/oban-bg/oban_web/commit/9998b7e284e02fdd4645dd6231760038e63b584d"
    },
    {
      "type": "WEB",
      "url": "https://github.com/oban-bg/oban_web/commit/a97c7960bb389b05aaab4cf8042985f02ceddc24"
    },
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-48593.html"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/oban-bg/oban_web"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-48593"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "oban_web: Unbounded range expansion in cron describe causes memory exhaustion"
}

CVE-2026-48593 (GCVE-0-2026-48593)

Vulnerability from cvelistv5 – Published: 2026-05-26 19:46 – Updated: 2026-05-27 15:40

Title

Unbounded range expansion in cron describe causes memory exhaustion in oban_web

Summary

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.

Severity

5.9 (Medium)


                        
                          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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-400 - Uncontrolled Resource Consumption

Assigner

EEF

References

4 references

URL	Tags
https://github.com/oban-bg/oban_web/security/advi…	vendor-advisoryrelated
https://cna.erlef.org/cves/CVE-2026-48593.html	related
https://osv.dev/vulnerability/EEF-CVE-2026-48593	related
https://github.com/oban-bg/oban_web/commit/9998b7…	patch

Impacted products

2 products

Vendor	Product	Version
oban-bg	oban_web	Affected: 2.12.0 , < 2.12.5 (semver) cpe:2.3:a:oban_web_project:oban_web::::::::
oban-bg	oban_web	Affected: a97c7960bb389b05aaab4cf8042985f02ceddc24 , < 9998b7e284e02fdd4645dd6231760038e63b584d (git) cpe:2.3:a:oban_web_project:oban_web::::::::

Credits

Peter Ullrich Shannon Selbert Jonatan Männchen / EEF

Show details on NVD website

JSON

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-6XH2-93P9-VQH4

Summary

Details

PoC

Impact

References

CVE-2026-48593 (GCVE-0-2026-48593)

Tags

Sightings

Nomenclature