Vulnerability 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.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://github.com/srvrco/getssl/pull/896
- https://github.com/srvrco/getssl/releases/tag/v2.50
- 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-2026-1
FAQ
What is CVE-2026-10303?
CVE-2026-10303 is a vulnerability with a CVSS score of 7.4 (HIGH). 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 maliciou...
How severe is CVE-2026-10303?
CVE-2026-10303 has been rated HIGH with a CVSS base score of 7.4/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-10303?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.