CVE-2026-1761 in libsoup
Summary
by MITRE • 02/02/2026
A flaw was found in libsoup. This stack-based buffer overflow vulnerability occurs during the parsing of multipart HTTP responses due to an incorrect length calculation. A remote attacker can exploit this by sending a specially crafted multipart HTTP response, which can lead to memory corruption. This issue may result in application crashes or arbitrary code execution in applications that process untrusted server responses, and it does not require authentication or user interaction.
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Analysis
by VulDB Data Team • 02/17/2026
The vulnerability identified as CVE-2026-1761 represents a critical stack-based buffer overflow within the libsoup library, a widely-used HTTP client library for applications built on the GNOME platform and other Unix-like systems. This flaw manifests during the processing of multipart HTTP responses, where the library fails to properly calculate the length of data structures, creating an exploitable condition that can be leveraged by remote attackers without any authentication requirements or user interaction. The vulnerability resides in the core parsing logic of the HTTP response handling mechanism, specifically when the library attempts to parse multipart content that contains multiple parts separated by boundary markers.
The technical implementation of this vulnerability stems from improper bounds checking during the parsing of HTTP multipart responses, which directly maps to CWE-121 Stack-based Buffer Overflow as defined in the Common Weakness Enumeration catalog. When libsoup encounters a malformed multipart response with oversized or improperly calculated content lengths, the library's internal buffer management fails to validate the data size against allocated memory boundaries. This incorrect length calculation allows an attacker to overflow the stack buffer and overwrite adjacent memory locations, potentially corrupting the program's execution flow. The attack vector is particularly dangerous because it operates entirely at the HTTP protocol level, making it accessible through standard network communication channels without requiring any privileged access or complex exploitation techniques.
The operational impact of CVE-2026-1761 extends beyond simple application crashes to potentially enable arbitrary code execution within the context of affected applications. Any software that relies on libsoup for HTTP communication and does not properly validate or sanitize server responses becomes vulnerable to this attack, including web browsers, network monitoring tools, email clients, and various desktop applications. The lack of authentication requirements and user interaction makes this vulnerability particularly dangerous in environments where applications process untrusted network data automatically. Attackers can craft malicious HTTP responses containing oversized multipart content that triggers the buffer overflow when processed by vulnerable applications, potentially leading to complete system compromise depending on the privilege level of the affected application.
Mitigation strategies for this vulnerability should focus on immediate patching of the libsoup library to the latest secure versions that contain proper bounds checking and length validation mechanisms. System administrators should prioritize updating all affected applications that depend on libsoup, particularly those handling untrusted HTTP responses from external sources. Network-level defenses such as web application firewalls and HTTP traffic filtering can provide additional protection by inspecting multipart content and blocking suspicious responses before they reach vulnerable applications. The ATT&CK framework categorizes this vulnerability under T1210 Exploitation for Credential Access and T1059 Command and Scripting Interpreter, as attackers may leverage this vulnerability to execute arbitrary code and potentially escalate privileges. Organizations should also implement runtime monitoring and intrusion detection systems to identify potential exploitation attempts targeting this specific buffer overflow condition, while maintaining comprehensive vulnerability management processes to prevent similar issues in other components of their software infrastructure.