CVE-2026-15714
Description
An out-of-bounds read vulnerability was found in libsoup's multipart processing subsystem. The flaw exists in the soup_multipart_input_stream_read_headers() function inside soup-multipart-input-stream.c, which does not adequately restrict or validate the size of incoming multipart boundary strings. When processing a crafted HTTP response containing a malformed or oversized boundary parameter, the internal stream reader reads past the allocated buffer bounds. A remote, unauthenticated attacker can exploit this behavior to cause a service denial (DoS) through application failure or potentially read fragments of unauthorized memory metadata.
Statement
This vulnerability presents a moderate risk to confidentiality and availability for software implementations implementing libsoup for multipart payload handling. Because the memory tracking misalignment happens during the automated header ingestion phase, an attacker can seamlessly induce a crash remotely without needing local context or user interaction. Red Hat Product Security ranks this as a notable security regression within parsing utilities, though impact vectors generally manifest as localized client or server session instability rather than complete remote code execution.
Mitigation
To mitigate this issue, restrict network access to applications that utilize libsoup for processing multipart messages from untrusted sources. Implement firewall rules to limit incoming connections to only trusted clients, thereby reducing the attack surface. If the vulnerable component is part of a service, ensure that the service is not exposed to untrusted networks.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.5 | N/A | 6.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | Low | N/A | Low |
| Integrity Impact | None | N/A | None |
| Availability Impact | Low | N/A | Low |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.
Confidentiality
Technical Impact: Bypass Protection Mechanism
Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string.
Other
Technical Impact: Varies by Context
The read operation could produce other undefined or unexpected results.
Acknowledgements
Red Hat would like to thank cavid for reporting this issue.
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