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TI-2026-31951 Aliases CVE-2026-43887

Outline: Stored XSS via Comment Mentions

Priority HIGH 67CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Required
Attack complexity
Low
Impact type
Cross-site scripting
Confidentiality · integrity · availability
High · High · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-79.

Summary

Outline is a service that allows for collaborative documentation. From 0.84.0 to 1.6.1, the Outline comment section permits users to mention other users; however, the backend does not validate or sanitize the href attribute associated with these mentions. As a result, potentially dangerous protocols (e.g., javascript:) are not filtered, introducing a risk of client-side code execution. This vulnerability is fixed in 1.7.0.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00245 15th percentileScored 2026-11-07
Fix Fixed outline (outline): 1.7.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Total

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

Affected products

VendorProductAffected versionsFixed inStatusSource
outlineoutline0.84.0 to before 1.7.01.7.0Patch availableCNA
  • outline Vendoroutline Affected 0.84.0 to before 1.7.0 Fixed in 1.7.0 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

  • Fix · CNA outline (outline) Fixed in 1.7.0

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-43887

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