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Vulnerability record · CVE-2026-10303 · published 16 June 2026

CVE-2026-10303: In ServerCo getssl version 2.49 and prior, the ACME challenge token returned to the client was not strictly va…

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.

7.4 CVSS 3.1 High EPSS 0.76% · top 46.6% CWE-73 · CWE-73 Awaiting Analysis
7.4CVSS 3.1 base score
0.76%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
5References
17 Jun 2026Last modified by NVD

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:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

References

LinkTags
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-2026-10303/

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Source: NIST National Vulnerability Database (record CVE-2026-10303), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.