---
id: CVE-2026-75583
title: >-
  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 aga…
summary: >-
  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 aga…
severity: low
cvss: 3.5
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N'
cwe:
  - CWE-918
published: '2026-08-19'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T20:06:30.133'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-75583'
references:
  - url: 'https://github.com/ridafkih/keeper.sh'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/ridafkih/keeper.sh/commit/aea1cf537b850509e802b388f38cf1482cb6291b
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/ridafkih/keeper.sh/security/advisories/GHSA-mxxg-qffg-j3p6
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/keeper-sh-calendar-version-prior-to-ssrf-guard-bypass-via-dns-rebinding
    label: disclosure@vulncheck.com
tags:
  - nvd
epss: 0.00325
epssPercentile: 0.22838
ingestedAt: '2026-09-24T20:51:40.209Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.