Summary
Package updates are available for Amazon Linux 2023 that fix the following vulnerabilities: CVE-2026-4519: The webbrowser.open() API would accept leading dashes in the URL which could be handled as command line options for certain web browsers. New behavior rejects leading dashes. Users are recommended to sanitize URLs prior to passing to webbrowser.open(). CVE-2026-4224: When an Expat parser with a registered ElementDeclHandler parses an inline document type definition containing a deeply nested content model a C stack overflow occurs. CVE-2026-2297: The import hook in CPython that handles legacy *.pyc files (SourcelessFileLoader) is incorrectly handled in FileLoader (a base class) and so does not use io.open_code() to read the .pyc files. sys.audit handlers for this audit event therefore do not fire. CVE-2026-1299: The email module, specifically the "BytesGenerator" class, didn't properly quote newlines for email headers when serializing an email message allowing for header injection when an email is serialized. This is only applicable if using "LiteralHeader" writing headers that don't respect email folding rules, the new behavior will reject the incorrectly folded headers in "BytesGenerator". CVE-2026-0865: User-controlled header names and values containing newlines can allow injecting HTTP headers. CVE-2026-0672: When using http.cookies.Morsel, user-controlled cookie values and parameters can allow injecting HTTP headers into messages. Patch rejects all control characters within cookie names, values, and parameters. CVE-2025-15282: User-controlled data URLs parsed by urllib.request.DataHandler allow injecting headers through newlines in the data URL mediatype. CVE-2025-11468: When folding a long comment in an email header containing exclusively unfoldable characters, the parenthesis would not be preserved. This could be used for injecting headers into email messages where addresses are user-controlled and not sanitized.
Fixed packages 10
| Release | Package | Fixed in |
|---|---|---|
| Amazon Linux · 2023 | python-unversioned-command | 0:3.9.25-1.amzn2023.0.4 |
| Amazon Linux · 2023 | python3 | 0:3.9.25-1.amzn2023.0.4 |
| Amazon Linux · 2023 | python3-debug | 0:3.9.25-1.amzn2023.0.4 |
| Amazon Linux · 2023 | python3-devel | 0:3.9.25-1.amzn2023.0.4 |
| Amazon Linux · 2023 | python3-idle | 0:3.9.25-1.amzn2023.0.4 |
| Amazon Linux · 2023 | python3-libs | 0:3.9.25-1.amzn2023.0.4 |
| Amazon Linux · 2023 | python3-test | 0:3.9.25-1.amzn2023.0.4 |
| Amazon Linux · 2023 | python3-tkinter | 0:3.9.25-1.amzn2023.0.4 |
| Amazon Linux · 2023 | python3.9-debuginfo | 0:3.9.25-1.amzn2023.0.4 |
| Amazon Linux · 2023 | python3.9-debugsource | 0:3.9.25-1.amzn2023.0.4 |
Vulnerabilities 8
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High 7.0
webbrowser.open() allows leading dashes in URLs
The webbrowser.open() API would accept leading dashes in the URL which could be handled as command line options for certain web browsers. New behavior rejects leading dashes. Users are recommended to sanitize URLs prior to passing to webbrowser.open().
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Medium 6.0
Header injection via newlines in data URL mediatype
User-controlled data URLs parsed by urllib.request.DataHandler allow injecting headers through newlines in the data URL mediatype.
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Medium 6.0
Header injection in http.cookies.Morsel
When using http.cookies.Morsel, user-controlled cookie values and parameters can allow injecting HTTP headers into messages. Patch rejects all control characters within cookie names, values, and parameters.
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Medium 6.0
email BytesGenerator header injection due to unquoted newlines
The email module, specifically the "BytesGenerator" class, didn’t properly quote newlines for email headers when serializing an email message allowing for header injection when an email is serialized. This is only applicable if using "LiteralHeader" writing h…
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Medium 6.0
Stack overflow parsing XML with deeply nested DTD content models
When an Expat parser with a registered ElementDeclHandler parses an inline document type definition containing a deeply nested content model a C stack overflow occurs.
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Medium 5.9
wsgiref.headers.Headers allows header newline injection
User-controlled header names and values containing newlines can allow injecting HTTP headers.
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Medium 5.7
Folding email comments of unfoldable characters doesn't preserve parenthesis
When folding a long comment in an email header containing exclusively unfoldable characters, the parenthesis would not be preserved. This could be used for injecting headers into email messages where addresses are user-controlled and not sanitized.
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Medium 5.7
SourcelessFileLoader does not use io.open_code()
The import hook in CPython that handles legacy *.pyc files (SourcelessFileLoader) is incorrectly handled in FileLoader (a base class) and so does not use io.open_code() to read the .pyc files. sys.audit handlers for this audit event therefore do not fire.
References
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web
https://alas.aws.amazon.com/cve/html/CVE-2025-11468.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2025-15282.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-0672.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-0865.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-1299.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-2297.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-4224.html
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web
https://alas.aws.amazon.com/cve/html/CVE-2026-4519.html