Information Exposure Through Timing Discrepancy in phpseclib - CVE-2026-32935

Vulnerability identifier: #VU125779

CSH Severity: Medium

CVSS v4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-32935

CWE-ID: CWE-208

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to disclose sensitive information.

The vulnerability exists due to observable timing discrepancy in AES-CBC unpadding when processing ciphertext in CBC mode. A remote attacker can send specially crafted ciphertext and measure response timing to disclose sensitive information.

phpseclib
Fedora
Ubuntu
phpseclib (Ubuntu package)
php-phpseclib3
nextcloud

Install security update from vendor's website.

phpseclib - addressed in versions 1.0.27, 2.0.52, 3.0.50
phpseclib (Ubuntu package) - addressed in versions 1.0.1-3ubuntu0.1+esm1, 1.0.9-1ubuntu0.1~esm2, 1.0.18-2ubuntu0.1~esm2, 1.0.20-1+deb12u3build0.22.04.1, 1.0.23-1ubuntu0.1~esm1, 1.0.24-1ubuntu0.1~esm1
php-phpseclib3 - addressed in versions 3.0.50-1.fc42, 3.0.50-1.fc43
nextcloud - addressed in versions 33.0.1-1.el10_1, 33.0.1-1.fc42

• https://github.com/phpseclib/phpseclib/security/advisories/GHSA-94g3-g5v7-q4jg
• https://github.com/advisories/GHSA-94g3-g5v7-q4jg

• Information Exposure Through Timing Discrepancy in phpseclib
• Fedora 43 update for php-phpseclib3
• Fedora 42 update for php-phpseclib3
• Fedora EPEL 10.1 update for nextcloud
• Fedora 42 update for nextcloud
• Ubuntu update for phpseclib