Bug 2528765 (CVE-2026-57166)

Summary: CVE-2026-57166 pjsip: pre-authentication overflow in the telnet CLI error
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
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Priority: high    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in PJSIP. A stack buffer overflow exists in the PJLIB-UTIL telnet CLI front-end when rendering feedback for an entered command line. A remote attacker, with access to the unauthenticated telnet CLI, can send an overly long command line to trigger this issue. This can cause an application termination, leading to a Denial of Service (DoS). This vulnerability only affects applications that have the telnet CLI front-end enabled.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2531102, 2531103, 2531104, 2531105    
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Description OSIDB Bzimport 2026-09-04 17:28:24 UTC 
PJSIP is a free and open source multimedia communication library written in C. Prior to commit 4472a31, a stack buffer overflow exists in the PJLIB-UTIL telnet CLI front-end when rendering feedback for an entered command line. Several command-line handling paths write an attacker-influenced amount of data into fixed-size buffers without sufficient bounds checking, so a long command line can overflow them. This affects only applications that enable the telnet CLI front-end (e.g. pj_cli_telnet_create() / --cli-telnet-port). The telnet CLI is an interactive administration interface with no authentication, so any client able to reach it can already issue arbitrary CLI commands. A malformed or overly long command line can overflow a fixed-size stack buffer while rendering command-line feedback, which may lead to application termination. Because reaching this code already requires access to the unauthenticated CLI, the impact beyond that existing access is limited. Applications that do not enable the telnet CLI front-end are not affected. This issue has been patched via commit 4472a31.