CVE-2026-110658 in sofia-sip
Summary
by MITRE • 10/14/2026
Sofia-SIP through 1.13.18 contains a heap out-of-bounds read vulnerability in msg_multipart_parse() that allows unauthenticated remote attackers to crash the process by sending oversized MIME boundaries. Attackers can send an INVITE with a multipart Content-Type whose boundary exceeds the body length, causing memcmp to read past the heap buffer and crash the process.
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Analysis
by VulDB Data Team • 10/14/2026
The vulnerability identified in Sofia-SIP versions up to 1.13.18 represents a critical security flaw within the session initiation protocol implementation, specifically located in the msg_multipart_parse function. This component is responsible for parsing multipart MIME content types, which are commonly used in VoIP communications to carry multiple parts of data within a single message body. The core technical deficiency lies in the lack of rigorous bounds checking when processing boundary strings defined by an attacker-controlled Content-Type header. When a remote unauthenticated actor sends an INVITE request containing a multipart Content-Type with a specified boundary length that exceeds the actual length of the provided body, the parsing logic fails to validate this discrepancy before proceeding with memory operations.
The immediate technical consequence is a heap-based out-of-bounds read triggered by the memcmp function. As the parser attempts to locate and verify the boundary string within the message body, it reads beyond the allocated heap buffer boundaries because the expected boundary length is artificially inflated in the header while the actual data payload remains short. This memory access violation does not necessarily allow for arbitrary code execution or information disclosure of sensitive kernel data due to the nature of a read-only overflow, but it inevitably leads to an immediate segmentation fault or process termination. The crash occurs during the parsing phase, meaning that any subsequent processing logic is never reached, resulting in a reliable denial-of-service condition against the Sofia-SIP stack hosting the vulnerable application server or user agent.
From an operational perspective, this vulnerability poses a significant risk to VoIP infrastructure stability. Since the attack requires no authentication and can be triggered by sending a single crafted SIP INVITE message, it is highly exploitable in open environments where IP telephony services are exposed to untrusted networks such as the public internet or compromised internal segments. The ability of an attacker to remotely crash the process disrupts call setup procedures and can lead to service outages for all users relying on that specific Sofia-SIP instance. In high-availability deployments, repeated exploitation could cause frequent restarts of critical signaling components, leading to degraded performance, dropped active calls, and increased operational overhead due to constant recovery cycles.
This flaw is categorized under CWE-125, which describes Out-of-bounds Read vulnerabilities, as the application accesses memory regions outside its intended boundaries. Furthermore, from a tactical standpoint aligned with MITRE ATT&CK frameworks, this vulnerability facilitates Denial of Service (T1499) by crashing service endpoints and potentially aids in Reconnaissance (T1595) if the crash behavior or error messages leak information about the software version or internal state to the attacker. The lack of input validation on MIME boundary parameters highlights a common oversight in protocol parsers where assumptions about message integrity are not strictly enforced before memory operations are executed.
To mitigate this risk, organizations running Sofia-SIP versions prior to 1.13.19 must apply the vendor-provided patch that corrects the bounds checking logic within msg_multipart_parse(). This update ensures that the parser validates the length of the boundary string against the actual body size before invoking memcmp or similar memory comparison functions. In environments where immediate patching is not feasible, network-level controls such as SIP application layer firewalls can be deployed to inspect incoming INVITE messages for malformed multipart headers and block requests with suspiciously large boundary declarations relative to their payload sizes. Additionally, implementing rate limiting on SIP signaling traffic can help mitigate the impact of automated exploitation attempts by reducing the frequency of crafted packets reaching vulnerable endpoints until a permanent fix is applied.