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

> Authenticated attackers can bypass SSRF guards via DNS rebinding to access private network resources and cloud metadata endpoints.

- **Severity:** Low 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`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 19 Aug 2026
- **Updated:** 21 Aug 2026
- **Also known as:** GHSA-mxxg-qffg-j3p6

## What is CVE-2026-75583?

CVE-2026-75583 is a low-severity server-side request forgery vulnerability in ridafkih keeper.sh, published on 19 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official 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: CWE-918 (Server-Side Request Forgery)

## Which versions are affected by CVE-2026-75583?


## How do I fix CVE-2026-75583?

No fix has been published for CVE-2026-75583 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-75583 being exploited?

There is no known exploitation of CVE-2026-75583 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-75583 and fix it if it is affected.

What it is: CVE-2026-75583 is a low-severity server-side request forgery vulnerability in ridafkih keeper.sh, published on 19 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-75583 in the wild and no public exploit code.

Affected product: ridafkih keeper.sh. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-75583/ (Markdown: https://insights.sbomify.com/CVE-2026-75583/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-75583
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-75583
- OSV: https://osv.dev/vulnerability/CVE-2026-75583

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-75583/
Summaries are generated and may contain mistakes; the official description above is the record.