Summary
It was discovered that the Net::IMAP client in Ruby did not properly
sanitize Symbol arguments passed to IMAP commands. A remote attacker
controlling a malicious IMAP server, or able to influence command
arguments, could use this to inject arbitrary IMAP commands via CRLF
sequences. (CVE-2026-42258)
It was discovered that the Zlib::GzipReader in Ruby did not correctly
ensure sufficient buffer capacity in the zstream_buffer_ungets function.
An attacker could use this to craft a gzip stream that, when processed,
could cause a buffer overflow, resulting in memory corruption and possibly
arbitrary code execution. (CVE-2026-27820)
Fixed packages 1
| Release | Package | Fixed in |
|---|---|---|
| Ubuntu · Pro 16.04 LTS Pro:16.04:LTS | ruby2.3 | 2.3.1-2~ubuntu16.04.16+esm15 |
Vulnerabilities 2
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Medium 5.8
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 IMA…
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Low 1.7
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…