# Phalcon: Catastrophic backtracking (ReDoS) in the default Phalcon Router route lead to remote unauthenticated DoS

Advisory record · `GHSA-x7rj-f32v-7jjg`

- **Identifiers:** `GHSA-x7rj-f32v-7jjg` · `CVE-2026-57584` · `PKSA-5stm-rfkw-zjbb`
- **State:** Confirmed
- **Severity:** CVSS 8.7 High
- **Critical:** No
- **Weakness (CWE):** [CWE-1333](https://cwe.mitre.org/data/definitions/1333.html)
- **Tags:** [Denial of service](https://agentprime.io/advisories/tag/dos.md)
- **Published:** 28 Aug 2026
- **Updated:** 28 Aug 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 28 Aug 2026, 16:06 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `phalcon/cphalcon` (Packagist): affected `<5.15.0`; fixed in `5.15.0`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Phalcon versions before 5.15.0 (phalcon/cphalcon on Packagist) are affected by catastrophic backtracking (ReDoS) in the default router pattern, which runs on every request. A remote, unauthenticated attacker can send a short request path containing a run of slashes followed by encoded newlines, which can make PHP's regex engine consume large amounts of CPU, with a single request taking seconds to minutes when PCRE JIT is disabled or the backtrack limit is raised. Upgrade to Phalcon 5.15.0 or later.

Written 31 Oct 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 8.7 High, CVSS 4.0: `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0053, the 45th percentile, on 14 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:07 UTC: First seen by agentprime
- 31 Oct 2026, 14:07 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-x7rj-f32v-7jjg)

## Sources

- [GitHub Advisory Database: GHSA-x7rj-f32v-7jjg](https://github.com/advisories/GHSA-x7rj-f32v-7jjg)
- [OSV: GHSA-x7rj-f32v-7jjg](https://osv.dev/vulnerability/GHSA-x7rj-f32v-7jjg)
- <https://github.com/phalcon/cphalcon/security/advisories/GHSA-x7rj-f32v-7jjg>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-57584>
- <https://github.com/phalcon/cphalcon/commit/14ba22d389d5ca620bb9d5207205f836ef1224f2>
- <https://github.com/phalcon/cphalcon/commit/fa798e919cb2c487062bb9899ad6fc2b673b3a67>
- <https://github.com/phalcon/cphalcon>
- <https://github.com/phalcon/cphalcon/releases/tag/v5.15.0>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-x7rj-f32v-7jjg>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-x7rj-f32v-7jjg/>. Everything for agents: <https://agentprime.io/llms.txt>.