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High, CVSS 8.7amended

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

CVE-2026-57584GHSA-x7rj-f32v-7jjg

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (phalcon/cphalcon 5.15.0), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS 4.0
8.7 · 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 · score source
EPSS
  • CVE-2026-57584: 0.53% estimated exploitation activity in the next 30 days; percentile 45.03 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Summary Every Phalcon MVC application built with a default router (new Phalcon\Mvc\Router() or new Phalcon\Mvc\Router(true), which is the normal case) registers a built-in route whose compiled PCRE pattern is #^/([\w0-9\\-]+)/([\w0-9\.\]+)(/.)$#u. The trailing (/.) is a nested quantifier whose group body (/.) overlaps itself (. matches /, and there is no s/DOTALL flag), so when the final $ is forced to fail the engine explores roughly 2^(N/2) ways to split a run of N slashes, causing classic catastrophic backtracking. Phalcon\Mvc\Router::handle() runs on every request and matches this pattern against the attacker-controlled request URI, so a single short request can burn seconds-to-minutes of CPU per request. The same (/.) construct is also produced by the /:params placeholder (Phalcon\Mvc\Router\Route::compilePattern()) and by the CLI router (Phalcon\Cli\Router / Phalcon\Cli\Router\Route). Details The vulnerable pattern is emitted in four places, all carrying the same nested…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 3 · amended ·

    Amended from ghsa record GHSA-x7rj-f32v-7jjg

  2. Revision 2 · amended ·

    Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

  3. Revision 1 · created ·

    Published from osv record GHSA-x7rj-f32v-7jjg

Agent brief

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# Patch Next advisory brief: CVE-2026-57584

Advisory: Phalcon: Catastrophic backtracking (ReDoS) in the default Phalcon Router route lead to remote unauthenticated DoS
IDs: CVE-2026-57584, GHSA-x7rj-f32v-7jjg
Record: https://patchnext.com/advisories/cve-2026-57584 (revision 3, source checked 26 Oct 2026, 14:50 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: phalcon/cphalcon 5.15.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist phalcon/cphalcon: affected <= 5.14.2; fixed in 5.15.0

## Suggested inspection (read-only)
- Packagist phalcon/cphalcon: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on phalcon/cphalcon.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-x7rj-f32v-7jjg (OSV record GHSA-x7rj-f32v-7jjg lists affected ranges: Packagist phalcon/cphalcon >=0 <5.15.0 (fixed))
- Verified: https://github.com/advisories/GHSA-x7rj-f32v-7jjg (GitHub-reviewed advisory GHSA-x7rj-f32v-7jjg lists affected ranges: Packagist phalcon/cphalcon >=0 <=5.14.2)

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