[Aikido] Fix security issue in urllib3 via major version upgrade from 1.23.0 to 2.6.3

[aikido-autofix]

Upgrade urllib3 to fix information disclosure via HTTP redirects, SSL certificate verification bypass, decompression bomb DoS attacks, and CRLF injection vulnerabilities. This update includes breaking changes that require manual migration.

⚠️ Code affected by breaking changes.

The urllib3 upgrade from 1.23 to 2.6.3 has breaking changes that affect this codebase:

1. Breaking Change: requests.packages.urllib3 access pattern no longer works

• Where your code is affected: elastalert/alerts.py in the HipChatAlerter.alert() method (around line 1850) and StrideAlerter.alert() method (around line 2450)

• Impact: The code uses requests.packages.urllib3.disable_warnings() to suppress SSL warnings. In urllib3 2.x, the vendored urllib3 inside requests is no longer accessible via requests.packages.urllib3. This will cause an AttributeError when hipchat_ignore_ssl_errors or stride_ignore_ssl_errors is set to True.

• Remediation: Replace requests.packages.urllib3.disable_warnings() with direct urllib3 import: import urllib3; urllib3.disable_warnings() or use the warnings module to suppress specific warning categories.

2. Breaking Change: Python 2.7 support removed

• Where your code is affected: The entire codebase is written for Python 2.7 as indicated in setup.py (classifier: 'Programming Language :: Python :: 2.7'), uses Python 2.7 specific imports like from HTMLParser import HTMLParser, and has Python 2.6 compatibility code in elastalert/util.py and elastalert/elastalert.py.

• Impact: urllib3 2.0+ requires Python 3.7+. The application will fail to install or run with urllib3 2.6.3 on Python 2.7, which is the only supported Python version according to the setup.py configuration.

• Remediation: Either keep urllib3 pinned to <2.0 (e.g., urllib3<2.0) or migrate the entire codebase to Python 3.7+, which would require significant refactoring of Python 2-specific code.

All breaking changes by upgrading urllib3 from version 1.23 to 2.6.3 (CHANGELOG)

Version	Description
1.24.0	Drop support for EOL Python 2.6
1.25.0	Require and validate certificates by default when using HTTPS
1.25.0	Upgraded urllib3.utils.parse_url() to be RFC 3986 compliant
1.25.0	Switched the default multipart header encoder from RFC 2231 to HTML 5 working draft
1.25.0	Drop ciphers using DSS key exchange from default TLS cipher suites
2.0.0	Removed support for Python 2.7, 3.5, and 3.6
2.0.0	Removed fallback on certificate commonName in match_hostname() function
2.0.0	Removed support for Python with an ssl module compiled with LibreSSL, CiscoSSL, wolfSSL, and all other OpenSSL alternatives
2.0.0	Removed support for OpenSSL versions earlier than 1.1.1 or that don't have SNI support
2.0.0	Removed the list of default ciphers for OpenSSL 1.1.1+ and SecureTransport
2.0.0	Removed urllib3.contrib.appengine.AppEngineManager and support for Google App Engine Standard Environment
2.0.0	Removed deprecated Retry options method_whitelist, DEFAULT_REDIRECT_HEADERS_BLACKLIST
2.0.0	Removed urllib3.HTTPResponse.from_httplib
2.0.0	Removed default value of None for the request_context parameter of urllib3.PoolManager.connection_from_pool_key
2.0.0	Removed the urllib3.request module
2.0.0	Removed support for SSLv3.0 from the urllib3.contrib.pyopenssl
2.0.0	Removed the deprecated urllib3.contrib.ntlmpool module
2.0.0	Removed DEFAULT_CIPHERS, HAS_SNI, USE_DEFAULT_SSLCONTEXT_CIPHERS from the private module urllib3.util.ssl_
2.0.0	Removed urllib3.exceptions.SNIMissingWarning
2.0.0	Removed the _prepare_conn method from HTTPConnectionPool
2.0.0	Removed tls_in_tls_required property from HTTPSConnection
2.0.0	Removed the strict parameter/attribute from HTTPConnection, HTTPSConnection, HTTPConnectionPool, HTTPSConnectionPool, and HTTPResponse
2.0.0	Changed urllib3.response.HTTPResponse.read to respect the semantics of io.BufferedIOBase regardless of compression
2.0.0	Changed urllib3.HTTPConnection.getresponse to return an instance of urllib3.HTTPResponse instead of http.client.HTTPResponse
2.0.0	Changed default SSLContext.minimum_version to be TLSVersion.TLSv1_2
2.0.0	Changed urllib3.util.create_urllib3_context to not override the system cipher suites with a default value
2.0.0	Changed multipart/form-data header parameter formatting matches the WHATWG HTML Standard as of 2021-06-10
2.0.0	Changed the error raised when connecting via HTTPS when the ssl module isn't available from SSLError to ImportError
2.0.0	Changed enforce_content_length default to True
2.0.0	Changed all parameters in the HTTPConnection and HTTPSConnection constructors to be keyword-only except host and port
2.0.0	Changed HTTPResponse.read() to raise an error when calling with decode_content=False after using decode_content=True
2.1.0	Removed support for the deprecated urllib3[secure] extra
2.1.0	Removed support for the deprecated SecureTransport TLS implementation
2.1.0	Removed support for the end-of-life Python 3.7
2.3.0	Removed support for Python 3.8
2.6.0	Removed the HTTPResponse.getheaders() method in favor of HTTPResponse.headers
2.6.0	Removed the HTTPResponse.getheader(name, default) method in favor of HTTPResponse.headers.get(name, default)
2.6.0	The number of allowed chained encodings is now limited to 5

✅ 10 CVEs resolved by this upgrade

This PR will resolve the following CVEs:

Issue	Severity	Description
CVE-2023-43804	MEDIUM	[urllib3] A vulnerability allows unintended cookie leakage via HTTP redirects to different origins when users specify a Cookie header without explicitly disabling redirects. This can lead to information disclosure as sensitive cookie data may be exposed to unintended recipients.
CVE-2019-11324	LOW	[urllib3] SSL certificate verification can be bypassed when custom CA certificates are specified, allowing connections that should fail to succeed due to improper handling of certificate validation contexts.
CVE-2025-66471	LOW	[urllib3] The Streaming API improperly handles highly compressed data, allowing attackers to cause excessive CPU usage and massive memory allocation through decompression of small compressed payloads. This results in a denial-of-service vulnerability via resource exhaustion.
CVE-2026-21441	LOW	[urllib3] Decompression bomb vulnerability in streaming API for HTTP redirects. Malicious servers can trigger excessive resource consumption by sending compressed redirect responses that are fully decompressed without respecting read limits.
CVE-2020-26137	LOW	[urllib3] before 1.25.9 allows CRLF injection if the attacker controls the HTTP request method, as demonstrated by inserting CR and LF control characters in the first argument of putrequest(). NOTE: this is similar to CVE-2020-26116.
CVE-2024-37891	LOW	[urllib3] The Proxy-Authorization header is not stripped during cross-origin redirects when set manually without using urllib3's proxy support, potentially leaking authentication credentials to malicious origins. This vulnerability requires manual header configuration, enabled redirects, and specific redirect conditions to be exploited.
CVE-2018-25091	LOW	[urllib3] Authorization header is not removed when following cross-origin redirects, potentially exposing credentials to unintended hosts or transmitting them in cleartext.
CVE-2019-11236	LOW	[urllib3] In the urllib3 library through 1.24.1 for Python, CRLF injection is possible if the attacker controls the request parameter.
CVE-2025-50181	LOW	[urllib3] A vulnerability allows disabling redirects for all requests through improper PoolManager instantiation with retries configuration, potentially bypassing SSRF and open redirect mitigations. Applications relying on disabled redirects to prevent these vulnerabilities remain exposed to attacks.
CVE-2023-45803	LOW	[urllib3] HTTP redirect responses (301, 302, 303) fail to remove request bodies when changing POST to GET, potentially leaking sensitive data to malicious redirect destinations. This information disclosure vulnerability requires a compromised trusted service to exploit.

🔗 Related Tasks

• https://humansecurity.atlassian.net/browse/AIKIDO-460
• https://humansecurity.atlassian.net/browse/AIKIDO-1260