CVE-2026-121109 in Chrome
Summary
by MITRE • 11/03/2026
Inadequate encryption strength in SSL in Google Chrome prior to 157.0.8103.38 allowed a remote attacker to potentially bypass web origin policy via crafted network traffic. (Chromium security severity: Low)
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Analysis
by VulDB Data Team • 11/03/2026
The vulnerability identified as an inadequate encryption strength issue within the Secure Sockets Layer implementation of Google Chrome prior to version 157.0.8103.38 represents a significant deviation from modern cryptographic best practices. This flaw specifically affects how the browser handles SSL/TLS connections, potentially allowing for the use of weaker cipher suites or protocol versions that are susceptible to known cryptanalytic attacks. The core technical failure lies in the negotiation phase where the client and server agree on encryption parameters. If the implementation fails to strictly enforce minimum security standards or incorrectly prioritizes legacy protocols such as TLS 1.0 or SSL 3.0, it creates an avenue for attackers to exploit mathematical weaknesses inherent in these older algorithms. These weaknesses can include vulnerabilities like BEAST or POODLE which rely on predictable initialization vectors or padding oracle attacks respectively. By leveraging crafted network traffic that mimics legitimate handshake sequences but exploits these specific cryptographic flaws, a remote attacker can potentially decrypt sensitive data transmitted over the connection or manipulate the communication stream without detection by standard security controls.
The operational impact of this vulnerability centers on the potential bypassing of web origin policies, which are fundamental to browser security models designed to isolate content from different sources. Origin policies prevent malicious scripts on one page from accessing resources on another page with a different origin, thereby mitigating cross-site scripting and data theft attacks. When encryption strength is insufficient, an attacker positioned in the network path can perform man-in-the-middle operations more effectively than if strong encryption were enforced. By decrypting or altering traffic that should be protected by robust cryptographic guarantees, the attacker can inject malicious content or exfiltrate sensitive information such as session cookies and authentication tokens. This undermines the confidentiality and integrity of web communications, allowing attackers to impersonate users or services legitimately accessed through Chrome. Although classified with a low severity rating in Chromium security assessments, this does not diminish its potential for exploitation in environments where legacy systems are still supported or where network conditions force fallbacks to weaker protocols.
From an industry standards perspective, this vulnerability aligns closely with CWE-327 which denotes the use of a broken or risky cryptographic algorithm. It also relates to CWE-614 concerning sensitive cookies without strict transport security if the encryption failure leads to cookie leakage. In terms of attack vectors and tactics, this scenario maps to MITM0008 in the ATT&CK framework, specifically involving network sniffing and credential harvesting through protocol downgrade attacks or weak cipher exploitation. The mitigation strategy primarily involves ensuring that all clients are updated to version 157.0.8103.38 or later where these cryptographic enforcement mechanisms have been hardened. Additionally, organizations should enforce strict TLS policies at the server level by disabling support for SSL and early TLS versions and requiring strong cipher suites such as AES-GCM with SHA-256 or higher hash functions. Implementing HTTP Strict Transport Security headers can further prevent protocol downgrade attacks by instructing browsers to only connect via HTTPS using secure parameters, thereby closing the attack surface exploited by this vulnerability.