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TI-2026-76940 Aliases CVE-2026-113611GHSA-5w2f-v435-9jjc

Information disclosure in Outline via orphaned webhook subscriptions

Priority MEDIUM 64CWE-863Published · Updated

Key facts

Attack vector
Network
Privileges required
High
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Security bypass
Confidentiality · integrity · availability
High · None · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-863.

Summary

Outline before 1.8.0 fails to revoke access for deleted administrators (CWE-863, incorrect authorization), so they keep receiving document contents. UserDeletedProcessor never disables their WebhookSubscription rows, so former admins who registered webhooks before deletion receive full document bodies, including Markdown and Yjs data, for every matching workspace event. A remote user with high privileges can exploit this without user interaction, and the impact is limited to confidentiality. CISA's SSVC rates exploitation as poc.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Description from the CNA

Outline before 1.8.0 contains an improper access revocation vulnerability that allows deleted administrators to keep receiving document contents because UserDeletedProcessor never disables their WebhookSubscription rows. Former admins who registered webhooks before deletion continue receiving full document bodies, including Markdown and Yjs data, via DeliverWebhookTask for every matching workspace event.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00535 45th percentileScored 2026-11-07
Fix Fixed outline (outline): 1.8.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
outlineoutlinebefore 1.8.01.8.0Patch availableCNA
  • outline Vendoroutline Affected before 1.8.0 Fixed in 1.8.0 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:getoutline:outline:*:*:*:*:*:*:*:*——outline
  • cpe:2.3:a:getoutline:outline:*:*:*:*:*:*:*:* Versions — — ·outline

Remediation

Update Outline to version 1.8.0 or later, which fixes the flaw. The sources list no fixed version for Outline beyond 1.8.0.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

  • Fix · CNA outline (outline) Fixed in 1.8.0

Timeline

  1. 2026-10-20 Threatist record created from CVE-2026-113611
  2. 2026-10-21 Alias added: GHSA-5w2f-v435-9jjc
  3. 2026-10-22 Priority changed: MEDIUM → LOW
  4. 2026-10-23 CISA SSVC decision points changed
  5. 2026-10-23 Priority changed: LOW → MEDIUM

References

Patch 1

Advisory 1

Other 2

  • TI-2026-26021 Outline has a rate limit bypass that allows brute force of email login OTP CVSS 4.0CRITICAL 9.1
  • TI-2026-31952 Outline: Zip Extraction Path Escape via PATH_MAX Truncation in Collection Import CVSS 3.1HIGH 8.7
  • TI-2026-20086 Outline's IDOR allows unauthorized viewing and seizing of private deleted drafts CVSS 3.1HIGH 8.8
  • TI-2024-25167 An issue in Outline <= v0.76.1 allows attackers to execute a session hijacking attack via… CVSS 3.1HIGH 8.8
  • TI-2020-19165 Outline Service 1.3.3 - 'Outline Service ' Unquoted Service Path CVSS 4.0HIGH 8.5
  • TI-2026-83841 Outline exposes unpublished documents through public share links CVSS 4.0MEDIUM 6.9
See all 24 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences