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TI-2026-54212 Aliases CVE-2026-77866GHSA-97fv-h8pq-9grg

SSRF protection bypass in safeurl via IPv6 addresses and unresolvable hosts

Priority LOW 39CWE-636Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
Present
Impact type
—
Confidentiality · integrity · availability
High · Low · None
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

Server-Side Request Forgery (SSRF) vulnerability in Slab safeurl allows an attacker who controls a validated URL to reach internal network destinations the library is configured to block. Only IPv4 addresses are matched against the reserved ranges and the blocklist. Every other address is treated as matching nothing, so a destination that is rejected in its IPv4 form is accepted when written as an IPv6 address, IPv6 entries in the blocklist never match, and a host that resolves to no IPv4 address is accepted regardless of where it points. Deployments that rely on the allowlist instead are unaffected, because there an unmatched address is rejected. This issue affects safeurl: from 0.1.0 onward.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0048 41st percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
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
Slabsafeurl0.1.0 and later—No fix listedCNA
  • safeurl VendorSlab Affected 0.1.0 and later Fixed in — No fix listed CNA

CPE names CNA · 1

CPEVersionsRoleVendor
cpe:2.3:a:slab:safeurl:*:*:*:*:*:*:*:*——Slab
  • cpe:2.3:a:slab:safeurl:*:*:*:*:*:*:*:* Versions — — ·Slab

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-77866
  2. 2026-10-03 Alias added: GHSA-97fv-h8pq-9grg

References

Advisory 1

Other 2

  • TI-2026-54258 safeurl validated address is not bound to the request, allowing DNS rebinding CVSS 4.0CRITICAL 9.0
  • TI-2021-02246 A vulnerability in the HTML editor of Slab Quill 4.8.0 allows an attacker to execute… CVSS 3.1MEDIUM 6.1
  • TI-2025-13736 Quill 2.0.3 - Lack of data validation in HTML export allowing XSS CVSS 4.0MEDIUM 5.1

Sources

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