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Ruby vulnerabilities

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Published CVEs affecting Ruby products: 13 record(s), with severity, exploitation and fixes.

Exploited only (KEV) →

CVE-2026-54696 Low · 3.7 CWE-122 Jun 30, 2026
Ruby JSON: JSON generator heap buffer overflow when streaming to an IO
Ruby JSON is a JSON implementation for Ruby. Versions 2.9.0 through 2.19.8 are vulnerable to heap buffer overflow when the JSON generator is provided with an oversized streamed object. When streaming to an IO JSON.dump(obj, io) and JSON::State#generate(obj, io) can write past the internal JSON generator buffer when a streamed object contains an attacker-controlled string near 16 KB. Exploitation would result in a reliable process crash/denial of service. This issue has been fixed in version 2.19.9.
CVE-2026-47242 Medium · 5.8 CWE-77 Jun 22, 2026
Net::IMAP: Command Injection via ID command argument
Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to 0.6.5 and 0.5.15, when Net::IMAP#id is called with a hash argument, although the ID field value strings are correctly quoted (escaping quoted specials), they were not validated to prohibit CRLF sequences. While Net::IMAP#enable does process its arguments for aliases, it does not validate them as valid atoms (or as a list of valid atoms). The #to_s value is sent verbatim. Arguments to either command could be used by an attacker to inject arbitrary IMAP commands. This vulnerability is fixed in 0.6.5 and 0.5.15.
CVE-2026-47241 Low · 2.1 CWE-162 Jun 22, 2026
Net::IMAP: Denial of Service via incomplete raw argument validation
Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to 0.6.5 and 0.5.15, several Net::IMAP commands accept a raw string argument which is only validated to prevent CRLF injection and then sent verbatim. If this string is derived from user-controlled input, an attacker can force the next command to be absorbed as a continuation of the first command. This will cause the first command to eventually fail, but also prevents it from returning until another command is sent (from another thread). That other command will not return until the connection is closed. This vulnerability is fixed in 0.6.5 and 0.5.15.
CVE-2026-47240 Medium · 5.8 CWE-77 Jun 22, 2026
Net::IMAP: Command Injection via non-synchronizing literal in "raw" argument
Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to 0.6.5 and 0.5.15, several Net::IMAP commands accept a "raw data" argument that is sent verbatim after validation to prevent command injection. However, if a server does not support non-synchronizing literals, it may still be possible to inject arbitrary IMAP commands inside non-synchronizing literals. A server without support for non-synchronizing literals may interpret the "+}\r\n" as the end of a malformed command line and respond with a tagged BAD. In that case, the contents of the literal will be interpreted as one or more new pipelined commands, allowing a CRLF command injection attack to succeed. This affects criteria for #search and #uid_search; search_keys for #sort, #thread, #uid_sort, and #uid_thread; and attr for #fetch and #uid_fetch. This vulnerability is fixed in 0.6.5 and 0.5.15.
CVE-2026-42258 Medium · 5.3 CWE-77 May 9, 2026
net-imap: Command Injection via unvalidated Symbol inputs
Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.4.24, 0.5.14, and 0.6.4, symbol arguments to commands are vulnerable to a CRLF Injection / IMAP Command injection via Symbol arguments passed to IMAP commands. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.
CVE-2026-42257 Critical · 9.8 CWE-77 May 9, 2026
net-imap: Command Injection via "raw" arguments to multiple commands
Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.4.24, 0.5.14, and 0.6.4, several Net::IMAP commands accept a raw string argument that is sent to the server without validation or escaping. If this string is derived from user-controlled input, it may contain contain CRLF sequences, which an attacker can use to inject arbitrary IMAP commands. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.
CVE-2026-42256 Medium · 6.5 CWE-770 May 9, 2026
net-imap: Denial of service via high iteration count for `SCRAM-*` authentication
Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. From versions 0.4.0 to before 0.4.24, 0.5.0 to before 0.5.14, and 0.6.0 to before 0.6.4, when authenticating a connection with SCRAM-SHA1 or SCRAM-SHA256, a hostile server can perform a computational denial-of-service attack on the client process by sending a big iteration count value. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.
CVE-2026-42246 High · 7.4 CWE-392 May 9, 2026
net-imap vulnerable to STARTTLS stripping via invalid response timing
Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.3.10, 0.4.24, 0.5.14, and 0.6.4, a man-in-the-middle attacker can cause Net::IMAP#starttls to return "successfully", without starting TLS. This issue has been patched in versions 0.3.10, 0.4.24, 0.5.14, and 0.6.4.
CVE-2026-42245 High · 7.5 CWE-407 May 9, 2026
net-imap: Quadratic complexity when reading response literals
Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.4.24, 0.5.14, and 0.6.4, Net::IMAP::ResponseReader has quadratic time complexity when reading large responses containing many string literals. A hostile server can send responses which are crafted to exhaust the client's CPU for a denial of service attack. This issue has been patched in versions 0.4.24, 0.5.14, and 0.6.4.
CVE-2026-41316 High · 8.1 CWE-693 Apr 24, 2026
ERB has an @_init deserialization guard bypass via def_module / def_method / def_class
ERB is a templating system for Ruby. Ruby 2.7.0 (before ERB 2.2.0 was published on rubygems.org) introduced an `@_init` instance variable guard in `ERB#result` and `ERB#run` to prevent code execution when an ERB object is reconstructed via `Marshal.load` (deserialization). However, three other public methods that also evaluate `@src` via `eval()` were not given the same guard: `ERB#def_method`, `ERB#def_module`, and `ERB#def_class`. An attacker who can trigger `Marshal.load` on untrusted data in a Ruby application that has `erb` loaded can use `ERB#def_module` (zero-arg, default parameters) as a code execution sink, bypassing the `@_init` protection entirely. ERB 4.0.3.1, 4.0.4.1, 6.0.1.1, and 6.0.4 patch the issue.
CVE-2026-27820 Critical · 9.8 CWE-120 Apr 16, 2026
zlib: Buffer Overflow in Zlib::GzipReader ungetc via large input leads to memory corruption
zlib is a Ruby interface for the zlib compression/decompression library. Versions 3.0.0 and below, 3.1.0, 3.1.1, 3.2.0 and 3.2.1 contain a buffer overflow vulnerability in the Zlib::GzipReader. The zstream_buffer_ungets function prepends caller-provided bytes ahead of previously produced output but fails to guarantee the backing Ruby string has enough capacity before the memmove shifts the existing data. This can lead to memory corruption when the buffer length exceeds capacity. This issue has been fixed in versions 3.0.1, 3.1.2 and 3.2.3.
CVE-2026-33210 Critical · 9.1 CWE-134 Mar 20, 2026
Ruby JSON has a format string injection vulnerability
Ruby JSON is a JSON implementation for Ruby. From version 2.14.0 to before versions 2.15.2.1, 2.17.1.2, and 2.19.2, a format string injection vulnerability can lead to denial of service attacks or information disclosure, when the allow_duplicate_key: false parsing option is used to parse user supplied documents. This issue has been patched in versions 2.15.2.1, 2.17.1.2, and 2.19.2.
CVE-2025-61594 High · 7.5 CWE-200 Dec 30, 2025
URI Credential Leakage Bypass over CVE-2025-27221
URI is a module providing classes to handle Uniform Resource Identifiers. In versions 0.12.4 and earlier (bundled in Ruby 3.2 series) 0.13.2 and earlier (bundled in Ruby 3.3 series), 1.0.3 and earlier (bundled in Ruby 3.4 series), when using the + operator to combine URIs, sensitive information like passwords from the original URI can be leaked, violating RFC3986 and making applications vulnerable to credential exposure. This is a a bypass for the fix to CVE-2025-27221 that can expose user credentials. This issue has been fixed in versions 0.12.5, 0.13.3 and 1.0.4.