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CVE-2026-39461

select(2) file descriptor set overflow causes stack overflow

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in p9, p5, p14
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: total

Summary

libcasper(3) communicates with helper processes via UNIX domain sockets, and uses the select(2) system call to wait for data to become available. However, it does not verify that its socket descriptor fits within select(2)'s descriptor set size limit of FD_SETSIZE (1024). An attacker able to cause an application using libcasper(3) to allocate large file descriptors, e.g., by opening many descriptors and executing a program which is not careful to close them upon startup, may trigger stack corruption. If the target application runs with setuid root privileges, this could be used to escalate local privileges.

Timeline

  1. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: total

  2. CVE published
  3. Record last updated

Affected versions

  • FreeBSD FreeBSD

    From 15.0-RELEASE · fixed in p9; From 14.4-RELEASE · fixed in p5; From 14.3-RELEASE · fixed in p14

References 1

security.freebsd.org