CVE-2026-15712 in Linux
Summary
by MITRE • 07/14/2026
A heap buffer over-read vulnerability was discovered in libsoup's (versions: libsoup 3.0 to 3.7.0) HTTP/2 connection tracking framework. When the library processes an HTTP/2 GOAWAY frame, it improperly handles the "Additional Debug Data" payload by assuming the data stream is a safely NUL-terminated C-string. Because the parser lacks strict length-boundary verification before reading this data, a remote, unauthenticated attacker can intentionally send a malformed GOAWAY frame missing the appropriate null delimiter. This causes the library to read past the end of the allocated buffer, triggering an application crash that results in a denial of service (DoS), or potentially exposing fragments of memory contents.
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Analysis
by VulDB Data Team • 07/14/2026
This heap buffer over-read vulnerability exists within libsoup's HTTP/2 connection tracking framework and represents a critical security flaw that can be exploited remotely without authentication. The vulnerability specifically manifests when the library processes HTTP/2 GOAWAY frames, which are standard protocol elements used to signal the end of communication between client and server. The flaw stems from improper handling of the "Additional Debug Data" payload section within these frames where the parser makes unsafe assumptions about data boundaries.
The technical implementation of this vulnerability relies on CWE-125, which describes out-of-bounds read conditions in software implementations. When libsoup encounters a GOAWAY frame, it attempts to parse the Additional Debug Data field by treating it as a null-terminated C-string without enforcing strict length validation. This approach creates an exploitable condition where attackers can craft malicious GOAWAY frames that lack proper null termination. The parser's failure to validate buffer boundaries before reading memory results in reading beyond allocated heap space, causing unpredictable behavior and system instability.
From an operational perspective, this vulnerability enables remote denial of service attacks that can disrupt HTTP/2 services relying on libsoup. The attack requires no authentication or privileged access, making it particularly dangerous for publicly accessible web servers, proxy systems, and applications that process HTTP/2 traffic. When exploited successfully, the buffer over-read causes application crashes that terminate service availability, while in some implementations, the memory read operations might expose sensitive fragments of adjacent memory contents, potentially revealing confidential information. The vulnerability affects any system using libsoup versions with affected HTTP/2 handling code, particularly impacting web servers, reverse proxies, and client applications processing HTTP/2 connections.
The attack vector aligns with ATT&CK technique T1499.004 for network denial of service and represents a classic example of memory safety issues in C/C++ applications. Organizations should prioritize patching affected versions of libsoup to address this vulnerability, as immediate remediation is necessary to prevent exploitation. System administrators should monitor for unusual GOAWAY frame patterns in network traffic logs and implement network-level protections against malformed HTTP/2 frames. Additionally, maintaining updated security patches across all HTTP/2 implementations and considering alternative libraries with more robust memory handling practices can provide defense-in-depth measures against similar vulnerabilities. The vulnerability demonstrates the critical importance of proper bounds checking in network protocol parsers and highlights the need for rigorous input validation in security-critical software components.