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TI-2026-31954 Aliases CVE-2026-43890

Authorization bypass in outline

Priority HIGH 67CWE-639Published · Updated

Key facts

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

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-639.

Summary

Outline is a service that allows for collaborative documentation. From 0.84.0 to 1.7.0, the subscriptions.create API endpoint in server/routes/api/subscriptions/subscriptions.ts exhibits a broken authorization pattern. When both collectionId and documentId are supplied in the request, the route handler authorizes ONLY the collection branch (line 125 if (collectionId)), while the downstream subscriptionCreator command at server/commands/subscriptionCreator.ts writes the subscription against the documentId (which was never validated). The result is a subscription record pinning the attacker's user to a victim document the attacker has no read access to, on any team in the instance. The schema (server/routes/api/subscriptions/schema.ts) only enforces "at least one of collectionId/documentId" via .refine() — it does NOT enforce mutual exclusivity, so passing both is a valid, schema-conforming request. This vulnerability is fixed in 1.7.1.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00205 10th percentileScored 2026-11-07
Fix Fixed outline (outline): 1.7.1

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
outlineoutline0.82.1 to before 1.7.11.7.1Patch availableCNA
  • outline Vendoroutline Affected 0.82.1 to before 1.7.1 Fixed in 1.7.1 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

  • Fix · CNA outline (outline) Fixed in 1.7.1

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-43890

References

Other 1

  • 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