VULNERABILITY INTELLIGENCE

CVE-2026-75583

CVSS score2.3 LOW
EPSS probability0.33%
CISA KEVNot currently listed
Published2026-08-19
Last modified2026-09-24
CVSS vectorCVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N

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.

Weakness classification

  • CWE-918: Server-Side Request Forgery (SSRF)

Primary references