The OpenSSL Project has released a critical security advisory, addressing three significant vulnerabilities that could allow attackers to execute remote code and potentially recover private cryptographic keys.
These flaws affect multiple OpenSSL versions across different platforms and could lead to memory corruption, denial of service attacks, and unauthorized access to sensitive cryptographic materials.
The most severe vulnerability involves out-of-bounds memory operations in RFC 3211 Key Encryption Key (KEK) unwrap functionality, tracked as CVE-2025-9230 with moderate severity.
This flaw occurs when applications attempt to decrypt Cryptographic Message Syntax (CMS) messages using password-based encryption (PWRI).
The vulnerability triggers both out-of-bounds read and write operations, potentially leading to memory corruption that attackers could exploit to execute arbitrary code or cause system crashes.
Memory Corruption Vulnerability (CVE-2025-9230)
The first vulnerability, CVE-2025-9230, affects OpenSSL versions 3.5, 3.4, 3.3, 3.2, 3.0, 1.1.1, and 1.0.2 through improper handling of CMS message decryption.
When applications process maliciously crafted password-based encrypted CMS messages, the vulnerability triggers out-of-bounds memory access operations.
The out-of-bounds write component can cause memory corruption, potentially allowing attackers to overwrite critical memory regions and execute shellcode or arbitrary commands.
Security researchers from Aisle Research, led by Stanislav Fort, discovered this vulnerability on August 9th, 2025. The exploit requires specific conditions, including password-based encryption usage in CMS messages, which limits the attack surface since PWRI encryption support is rarely implemented in production environments. However, successful exploitation could result in complete system compromise through remote code execution capabilities.
The vulnerability exists in the KEK unwrap algorithm implementation, where insufficient bounds checking allows memory operations beyond allocated buffer boundaries.
Attackers can craft malicious CMS payloads that trigger integer overflow conditions, resulting in buffer overflows during decryption processes.
The FIPS modules remain unaffected since CMS implementation operates outside the OpenSSL FIPS boundary.
Timing Side-Channel Flaw (CVE-2025-9231)
The second critical flaw, CVE-2025-9231, introduces a timing side-channel vulnerability in the SM2 cryptographic algorithm implementation on 64-bit ARM platforms.
This vulnerability allows remote attackers to recover private keys through timing analysis of signature computation operations, according to the OpenSSL advisory.
While OpenSSL doesn’t directly support SM2 certificates in Transport Layer Security (TLS) contexts, custom providers could expose this vulnerability in production environments.
Timing side-channel attacks exploit variations in cryptographic operation execution times to extract sensitive information.
The SM2 algorithm implementation exhibits timing discrepancies during signature generation processes, creating measurable patterns that attackers can analyze to reconstruct private key material.
| CVE | Title | Severity |
| CVE-2025-9230 | Out-of-bounds read & write in RFC 3211 KEK Unwrap | Moderate |
| CVE-2025-9231 | Timing side-channel in SM2 algorithm on 64 bit ARM | Moderate |
| CVE-2025-9232 | Out-of-bounds read in HTTP client no_proxy handling | Low |
This attack vector requires network access to measure timing variations across multiple cryptographic operations, making it feasible for remote exploitation scenarios.
The vulnerability affects OpenSSL versions 3.5, 3.4, 3.3, and 3.2 specifically on 64-bit ARM architectures. Earlier versions, including 3.1, 3.0, 1.1.1, and 1.0.2, remain unaffected due to different implementation approaches.
Additionally, CVE-2025-9232 involves out-of-bounds read operations in HTTP client no_proxy handling for IPv6 addresses, though this presents a lower risk with denial-of-service impact only.
Organizations using custom cryptographic providers with SM2 support should prioritize immediate patching to prevent private key compromise through timing analysis attacks.
Immediate remediation requires upgrading to patched versions: OpenSSL 3.5.4, 3.4.3, 3.3.5, 3.2.6, 3.0.18, 1.1.1zd (premium support), and 1.0.2zm (premium support).
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