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CVE-2026-32935

phpseclib's AES-CBC unpadding susceptible to padding oracle timing attack

Also known asGHSA-94g3-g5v7-q4jg
Published
Mar 20, 2026
Updated
Apr 28, 2026
Affected
3 pkgs
Patched
3 / 3
Exploits
None indexed

EPSS Exploitation Probability

via FIRST.org ↗
0.4%probability of exploitation in next 30 days
Lower Risk29th percentile+0.36%
0.00%0.29%0.58%0.87%0.0%0.0%0.0%0.4%Apr 26Jun 26Jun 26

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

3 pkgs affected
🐘phpseclib/phpseclib🐘phpseclib/phpseclib🐘phpseclib/phpseclib

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

phpseclib is a PHP secure communications library. Projects using versions 1.0.26 and below, 2.0.0 through 2.0.51, and 3.0.0 through 3.0.49 are vulnerable to a to padding oracle timing attack when using AES in CBC mode. This issue has been fixed in versions 1.0.27, 2.0.52 and 3.0.50.

Affected Packages

3 total 3 fixed
EcosystemPackageVulnerable rangeFix
🐘Packagistphpseclib/phpseclib3.0.0&&< 3.0.503.0.50
🐘Packagistphpseclib/phpseclib2.0.0&&< 2.0.522.0.52
🐘Packagistphpseclib/phpseclib0.1.1&&< 1.0.271.0.27

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for phpseclib/phpseclib. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Fix

    Update phpseclib/phpseclib to 3.0.50 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-32935 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 pinpoints whether CVE-2026-32935 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2026-32935. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

phpseclib is a PHP secure communications library. Projects using versions 1.0.26 and below, 2.0.0 through 2.0.51, and 3.0.0 through 3.0.49 are vulnerable to a to padding oracle timing attack when using AES in CBC mode. This issue has been fixed in versions 1.0.27, 2.0.52 and 3.0.50.
O3 Security · Impact-Aware SCA

Is CVE-2026-32935 in your dependencies?

O3 detects CVE-2026-32935 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.