Bug 2573244 (CVE-2026-129122)

Summary: CVE-2026-129122 ckermit: ckermit: Memory corruption via crafted Telnet NEW-ENVIRON negotiation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in C-Kermit. A malicious or machine-in-the-middle Telnet server can trigger a buffer overflow by sending oversized variable names during Telnet NEW-ENVIRON subnegotiation prior to authentication. This issue allows the server to corrupt client stack and heap memory, potentially resulting in arbitrary code execution or a denial of service (DoS).
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Description OSIDB Bzimport 2026-11-13 16:32:09 UTC 
C-Kermit 6.0.192 before 11.1.515 contains a buffer overflow vulnerability in tn_snenv() in ckctel.c that allows malicious Telnet servers to corrupt client memory via crafted NEW-ENVIRON SEND subnegotiation. Malicious or machine-in-the-middle servers can send oversized variable names before authentication, overflowing a 16-byte stack buffer and a miscomputed heap buffer to corrupt stack and heap memory.