SB20260827142 - Information Exposure Through Timing Discrepancy in phpseclib

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Main Vulnerability Database SB20260827142

SB20260827142 - Information Exposure Through Timing Discrepancy in phpseclib

Published: August 27, 2026

Security Bulletin ID SB20260827142
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Local access
Highest impact Data manipulation

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Information Exposure Through Timing Discrepancy (CVE-ID: N/A)

CWE-ID: CWE-208 - Information Exposure Through Timing Discrepancy

CVSSv4: 7.2 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a local user to recover a private key.

The vulnerability exists due to observable timing discrepancy in the pure-PHP X25519 scalar multiplication implementation when performing scalar multiplication operations. A local user can observe per-ladder-step timing or libgmp call counts to recover a private key.

Exploitation requires a reused or long-lived X25519 private key, knowledge of the victim\'s public key, and execution of the pure-PHP path with per-ladder-step observation capability.


Remediation

Install update from vendor's website.

References