---
id: "CVE-2026-118993"
kind: "vulnerability"
aliases: ["CVE-2026-118993"]
title: "CallBackery Perl: crafted request path can stall a worker for minutes"
severity: "medium"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["callbackery", "cgi", "fastcgi", "package", "perl", "psgi"]
not_affected_if: ["no-cgi-fastcgi-psgi", "version-0.62.0-or-later"]
published_at: "2026-10-30T13:18:32+00:00"
first_seen_at: "2026-10-30T13:30:27+00:00"
updated_at: "2026-10-30T13:32:24+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-118993", "first_seen_at": "2026-10-30T13:30:27+00:00"}]
---

# CallBackery Perl: crafted request path can stall a worker for minutes

CallBackery for Perl builds a regular expression from the request path without escaping it, so a request with a crafted path makes the matcher backtrack exponentially. An unauthenticated remote client can keep a CGI, FastCGI or PSGI worker busy for minutes, which denies service.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed CallBackery version with `perl -MCallBackery -e 'print $CallBackery::VERSION'` or in the project's cpanfile or Makefile.PL
- Look for `startup()` and a `before_dispatch` hook that strips PATH_INFO from REQUEST_URI in the application code

## Fix

- CallBackery versions before `0.62.0` are affected; move to `0.62.0` or later

## Timeline

- 2026-10-30T13:30:27+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-118993

## From the sources

CallBackery versions before 0.62.0 for Perl allow denial of service via the request path interpolated as a regular expression under CGI, FastCGI and PSGI.

The before_dispatch hook installed by startup() removes PATH_INFO from the end of the request URI with a substitution that interpolates PATH_INFO unquoted. Under CGI, FastCGI and PSGI both values come from the request, so the client chooses both the pattern and the string it is matched against.

A short unauthenticated request with a backreference in the path backtracks exponentially and can keep a worker process busy for minutes.

---

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