ruby: missing "taintness" checks in dl module

The dl module in Ruby 1.8.5 and earlier, 1.8.6 through 1.8.6-p286, 1.8.7 through 1.8.7-p71, and 1.9 through r18423 does not check "taintness" of inputs, which allows context-dependent attackers to bypass safe levels and execute dangerous functions by accessing a library using DL.dlopen...

ruby: Unsafe use of alloca in rb_str_format()

The rbstrformat function in Ruby 1.8.4 and earlier, 1.8.5 before 1.8.5-p231, 1.8.6 before 1.8.6-p230, 1.8.7 before 1.8.7-p22, and 1.9.0 before 1.9.0-2 allows context-dependent attackers to trigger memory corruption via unspecified vectors related to alloca, a different issue than CVE-2008-2662,...

ruby: entity expansion DoS vulnerability in REXML

lib/rexml/text.rb in the REXML parser in Ruby before 1.9.3-p392 allows remote attackers to cause a denial of service memory consumption and crash via crafted text nodes in an XML document, aka an XML Entity Expansion XEE attack...

ruby: Properly initialize the random number generator when forking new process

Ruby before 1.8.7-p352 does not reset the random seed upon forking, which makes it easier for context-dependent attackers to predict the values of random numbers by leveraging knowledge of the number sequence obtained in a different child process, a related issue to CVE-2003-0900. NOTE: this issu...

ruby: SMTP command injection via CRLF sequences in RCPT TO or MAIL FROM commands in Net::SMTP

A SMTP command injection flaw was found in the way Ruby's Net::SMTP module handled CRLF sequences in certain SMTP commands. An attacker could potentially use this flaw to inject SMTP commands in a SMTP session in order to facilitate phishing attacks or spam campaigns...

ruby: integer overflow in rb_ary_splice/update/replace() - beg + rlen

Integer overflow in the 1 rbarysplice function in Ruby 1.8.4 and earlier, 1.8.5 before 1.8.5-p231, 1.8.6 before 1.8.6-p230, 1.8.7 before 1.8.7-p22, and 1.9.0 before 1.9.0-2; and 2 the rbaryreplace function in 1.6.x allows context-dependent attackers to trigger memory corruption, aka the "beg +...

ruby: multiple insufficient safe mode restrictions

Ruby 1.8.5 and earlier, 1.8.6 through 1.8.6-p286, 1.8.7 through 1.8.7-p71, and 1.9 through r18423 does not properly restrict access to critical variables and methods at various safe levels, which allows context-dependent attackers to bypass intended access restrictions via 1 untracevar, 2...

ruby: Murmur hash-flooding DoS flaw in ruby 1.9 (oCERT-2012-001)

Ruby aka CRuby 1.9 before 1.9.3-p327 and 2.0 before r37575 computes hash values without properly restricting the ability to trigger hash collisions predictably, which allows context-dependent attackers to cause a denial of service CPU consumption via crafted input to an application that maintains...

Moderate: Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update

An update for Red Hat Hardened Images RPMs is now available. This update includes the following RPMs: ruby4.0: ruby4.0-4.0.0-33.3.hum1 aarch64, x8664 ruby4.0-bundled-gems-4.0.0-33.3.hum1 aarch64, x8664 ruby4.0-default-gems-4.0.0-33.3.hum1 noarch ruby4.0-devel-4.0.0-33.3.hum1 aarch64, x8664...

ruby: Potential HTTP request smuggling in WEBrick

An issue was discovered in Ruby through 2.5.8, 2.6.x through 2.6.6, and 2.7.x through 2.7.1. WEBrick, a simple HTTP server bundled with Ruby, had not checked the transfer-encoding header value rigorously. An attacker may potentially exploit this issue to bypass a reverse proxy which also has a po...

EUVD-2026-23278

Buffer Overflow in Zlib::GzipReader ungetc via large input leads to memory corruption...

AZL-83450 CVE-2026-27820 affecting package ruby for versions less than 3.3.5-8

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 zstreambufferungets function prepends caller-provided bytes ahead of previously produced output but...

CVE-2026-27820

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 zstreambufferungets function prepends caller-provided bytes ahead of previously produced output but...

UBUNTU-CVE-2026-27820

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 zstreambufferungets function prepends caller-provided bytes ahead of previously produced output but...

CVE-2026-27820

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 zstreambufferungets function prepends caller-provided bytes ahead of previously produced output but...

CVE-2026-27820 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 zstreambufferungets function prepends caller-provided bytes ahead of previously produced output but...

CVE-2026-27820 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 zstreambufferungets function prepends caller-provided bytes ahead of previously produced output but...

CVE-2026-27820

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 zstreambufferungets function prepends caller-provided bytes ahead of previously produced output but...

CVE-2026-27820 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 zstreambufferungets function prepends caller-provided bytes ahead of previously produced output but...

CVE-2026-27820

CVE-2026-27820 is a buffer overflow in the Ruby zlib interface’s Zlib::GzipReader caused by zstream_buffer_ungets not ensuring sufficient Ruby string capacity before memmove. Affected: zlib gem v3.2.0/3.2.1 and earlier (3.0.0 and below, 3.1.0/3.1.1, 3.2.0/3.2.1). Impact: memory corruption when bu...