GHSA-2528-jw5q-ww88 is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in phpseclib/phpseclib. O3 Security confirms whether GHSA-2528-jw5q-ww88 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
phpseclib: guardrails needed on isPrime and randomPrime
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-2528-jw5q-ww88.
EPSS Exploitation Probability
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.
How urgent is this, really
GHSA-2528-jw5q-ww88 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 356,453 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
phpseclib/phpseclib🐘phpseclib/phpseclib🐘phpseclib/phpseclibReal-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
Impact
Anyone trying to generate a prime and testing the primality of a number.
Patches
https://github.com/phpseclib/phpseclib/commit/ad5dbdf2129f5e0fb644637770b7f33de8ca8575
Workarounds
Using the GMP extension would probably help, assuming that one has its own guardrails.
Resources
https://github.com/phpseclib/phpseclib/commit/ad5dbdf2129f5e0fb644637770b7f33de8ca8575 https://www.usenix.org/system/files/conference/usenixsecurity25/sec25cycle1-prepub-599-shi-bing.pdf
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | phpseclib/phpseclib | ≥ 0.1.1&&< 1.0.23 | 1.0.23 |
| 🐘Packagist | phpseclib/phpseclib | ≥ 2.0.0&&< 2.0.47 | 2.0.47 |
| 🐘Packagist | phpseclib/phpseclib | ≥ 3.0.0&&< 3.0.36 | 3.0.36 |
Detection & mitigation playbook
Open-source dependencyDetect
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.
Fix
Update phpseclib/phpseclib to 1.0.23 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-2528-jw5q-ww88 is resolved across your whole dependency graph.
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.
How O3 protects you
O3 pinpoints whether GHSA-2528-jw5q-ww88 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 GHSA-2528-jw5q-ww88. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Frequently Asked Questions
Is GHSA-2528-jw5q-ww88 in your dependencies?
O3 detects GHSA-2528-jw5q-ww88 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.