CVE-2026-22775: High Vulnerability in Svelte devalue

CVE-2026-22775 is a high-severity vulnerability in Svelte devalue, a JavaScript library that serializes values into strings when JSON.stringify is insufficient. This vulnerability affects versions from 5.1.0 to 5.6.1, where certain inputs can cause devalue.parse to consume excessive CPU time and/or memory. This can lead to denial of service in systems that parse input from untrusted sources, making it critical for organizations to address this issue.

The root cause of this vulnerability lies in the ArrayBuffer hydration process, which expects base64 encoded strings as input. However, it does not check this assumption before decoding the input, leading to potential resource exhaustion. This vulnerability has been fixed in version 5.6.2, released on January 15, 2026, following the discovery of the issue.

Organizations should prioritize patching immediately, as the exploitation potential for this vulnerability poses a significant risk. With a CVSS score of 7.5, the attack vector is classified as network-based, with low complexity and no privileges or user interaction required. This makes it easy for attackers to exploit vulnerable systems.

The urgency to remediate this vulnerability cannot be overstated. Organizations utilizing Svelte devalue should swiftly transition to version 5.6.2 to mitigate risks associated with denial of service attacks stemming from this vulnerability.

Vulnerability Details

Svelte devalue is a JavaScript library used for serializing values. The vulnerability, CVE-2026-22775, allows attackers to leverage the devalue.parse function in versions 5.1.0 through 5.6.1. It has a CVSS score of 7.5, indicating high severity. The vulnerability is classified under CWE-405, which concerns resource exhaustion.

Technical Analysis

The root cause of the vulnerability stems from how the ArrayBuffer hydration expects base64 encoded strings. When this assumption is violated, it can lead to excessive resource consumption. The attack vector is network-based, and the complexity of the attack is low. Attackers do not require any privileges or user interaction to exploit this vulnerability, making it a significant risk.

Risk & Impact Analysis

Risk to organizations includes potential denial of service due to excessive resource consumption. This vulnerability can affect any application utilizing devalue.parse with untrusted inputs. Given the high CVSS score of 7.5 and the possibility of exploitation without user interaction, organizations should assess their exposure and prioritize remediation based on their risk tolerance.

Exploitation Status

Affected Versions

The affected versions of Svelte devalue are from 5.1.0 to 5.6.1. Organizations should upgrade to version 5.6.2, which contains the fix for this vulnerability.

Mitigation & Remediation

Organizations should update to version 5.6.2 of Svelte devalue to remediate this vulnerability. For those unable to apply the patch immediately, it is advisable to implement input validation on externally supplied data to mitigate the risk of denial of service attacks. Additionally, consider implementing network controls to limit exposure.

Detection Guidance

Monitor for unusual CPU and memory usage patterns that may indicate attempts to exploit this vulnerability. Additionally, inspect logs for any anomalies related to input parsing in applications using devalue.parse.

AppSecure Threat Intelligence Insight

CVE-2026-22775 highlights the importance of rigorous input validation, particularly in libraries that handle external data. Security teams should incorporate lessons learned from this incident into their vulnerability management program, focusing on proactive measures to prevent similar vulnerabilities in the future.

For more insights on securing your applications, consider reading our articles on penetration testing methodology and vulnerability management program design for best practices.