CVE-2026-75583 json
keeper.sh Calendar version prior to 2.18.14 SSRF Guard Bypass via DNS Rebinding
published 2026-08-19 2 mo ago modified 2026-09-24 45 d ago also EUVD-2026-62585
- cvss
- 3.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 25%
- public exploits
- 0
- none known
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 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.
Patch / fix
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 2 mo ago
Exploit prediction
0.33% chance of exploitation in the next 30 days, higher than 25% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 2.3 | 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 |
| CNA | 3.1 | 3.5 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:N |
| CNA | 4.0 | 2.3 | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
Affected products
- ridafkih keeper.sh
Classification
- Weakness
-
- CWE-918 Server-Side Request Forgery
References
-
github.com
/ridafkih/keeper.sh/commit/aea1cf537b850509e802b388f38cf1482cb6291b
patch
-
github.com
/ridafkih/keeper.sh/security/advisories/GHSA-mxxg-qffg-j3p6
vendor-advisory
-
github.com
/ridafkih/keeper.sh
product
-
vulncheck.com
/advisories/keeper-sh-calendar-version-prior-to-ssrf-guard-bypass-via-dns-rebinding
third-party-advisory
Sources
- CVE List CVE-2026-75583
- NVD CVE-2026-75583
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.