CVE-2026-54906

Range taken from the CVE record, check it before committing. make newentry in security/vuxml creates the vid.

  <vuln vid="FIXME (make newentry)">
    <topic>FIXME -- FIXME</topic>
    <affects>
      <package>
	<name>rubygem-concurrent-ruby11</name>
	<range><lt>1.3.7</lt></range>
      </package>
    </affects>
    <description>
      <body xmlns="http://www.w3.org/1999/xhtml">
	<p>concurrent-ruby is a modern concurrency tools for Ruby. Prior to
	1.3.7, Concurrent::ReadWriteLock#release_write_lock does not verify
	that the calling thread acquired the write lock. Any thread with
	access to the lock object can release an active write lock held by
	another thread. A second writer can then enter its critical section
	while the first writer is still running.
	Concurrent::ReadWriteLock#release_read_lock also decrements the shared
	counter even when no read lock is held. Calling it on a fresh lock
	changes the counter from 0 to -1, after which normal read acquisition
	raises Concurrent::ResourceLimitError. This is a synchronization
	correctness issue in the public Concurrent::ReadWriteLock API. This
	vulnerability is fixed in 1.3.7.</p>
      </body>
    </description>
    <references>
      <cvename>CVE-2026-54906</cvename>
      <url>https://nvd.nist.gov/vuln/detail/CVE-2026-54906</url>
    </references>
    <dates>
      <discovery>2026-06-24</discovery>
      <entry>2026-10-26</entry>
    </dates>
  </vuln>