CVE-2010-5298 in OpenSSL
Summary
by MITRE
Race condition in the ssl3_read_bytes function in s3_pkt.c in OpenSSL through 1.0.1g, when SSL_MODE_RELEASE_BUFFERS is enabled, allows remote attackers to inject data across sessions or cause a denial of service (use-after-free and parsing error) via an SSL connection in a multithreaded environment.
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Analysis
by VulDB Data Team • 05/10/2026
The vulnerability identified as CVE-2010-5298 represents a critical race condition within the OpenSSL cryptographic library that affects versions through 1.0.1g. This flaw specifically manifests in the ssl3_read_bytes function located in the s3_pkt.c file, creating a dangerous scenario when the SSL_MODE_RELEASE_BUFFERS flag is activated. The race condition occurs in multithreaded environments where concurrent access to shared resources can lead to unpredictable behavior and security breaches. The vulnerability stems from improper synchronization mechanisms that fail to adequately protect shared memory structures during SSL session processing, creating opportunities for malicious exploitation.
The technical implementation of this vulnerability involves a complex interaction between thread scheduling and memory management within the OpenSSL library. When SSL_MODE_RELEASE_BUFFERS is enabled, the library attempts to optimize memory usage by releasing buffers that are no longer needed during SSL session processing. However, the race condition arises when multiple threads access the same buffer simultaneously, with one thread potentially freeing memory while another thread attempts to read from or write to that same memory location. This creates a classic use-after-free scenario where memory is accessed after it has been deallocated, leading to potential code execution or denial of service conditions.
The operational impact of CVE-2010-5298 extends beyond simple denial of service to encompass serious data integrity concerns and potential remote code execution capabilities. Attackers can exploit this vulnerability to inject arbitrary data across different SSL sessions, effectively breaking the security boundaries that should separate distinct connections. The parsing errors that occur as a result of this race condition can cause the SSL library to crash or behave unpredictably, leading to service disruption. From a cybersecurity perspective, this vulnerability directly relates to CWE-362, which describes race conditions in software development, and aligns with ATT&CK techniques involving privilege escalation and resource hijacking. The vulnerability's exploitation requires a multithreaded environment, making it particularly dangerous in high-concurrency web servers and application environments.
Mitigation strategies for CVE-2010-5298 primarily focus on immediate patching of affected OpenSSL versions, with the release of OpenSSL 1.0.1h and subsequent versions addressing the race condition through improved thread synchronization mechanisms. Organizations should disable SSL_MODE_RELEASE_BUFFERS in production environments until proper patches are applied, as this flag is often enabled for performance optimization but creates the conditions necessary for exploitation. Additionally, implementing proper thread management practices and ensuring that all SSL connections are properly synchronized can help reduce the attack surface. Network segmentation and monitoring for unusual SSL connection patterns can provide early detection of potential exploitation attempts. The vulnerability serves as a critical reminder of the importance of proper memory management in cryptographic libraries and the need for comprehensive thread safety testing in security-critical software components.