CVE-2023-49316: 
PHP vulnerability analysis and mitigation

CVE-2023-49316 affects phpseclib 3 versions before 3.0.34, specifically in the Math/BinaryField.php component. The vulnerability was disclosed on November 27, 2023, and involves a denial of service condition triggered by excessively large degrees in binary field operations (NVD, Ubuntu).

The vulnerability exists in the Math/BinaryField.php component and is triggered when processing excessively large degrees in binary field operations. The issue has been assigned a CVSS v3.1 base score of 7.5 (High) with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H, indicating it can be exploited remotely with low attack complexity and requires no privileges or user interaction (NVD).

When successfully exploited, the vulnerability can lead to a denial of service condition, affecting the availability of the system. The impact is limited to availability with no direct effect on confidentiality or integrity (Ubuntu).

The vulnerability has been fixed in phpseclib version 3.0.34. The fix implements a limit on the maximum degree size (571), which is based on the largest binary curves defined in SEC2-V2 specifications. Users are advised to upgrade to version 3.0.34 or later (Github Patch).