select(2) file descriptor set overflow causes stack overflow

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Summary

CVECVE-2026-39461
StatePUBLISHED
Assignerfreebsd
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-21 10:16:25 UTC
Updated2026-05-21 19:01:35 UTC
Descriptionlibcasper(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.

Risk And Classification

Primary CVSS: v3.1 8.8 HIGH from ADP

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

EPSS: 0.000060000 probability, percentile 0.004460000 (date 2026-05-27)

Problem Types: CWE-121 | CWE-121 CWE-121: Stack-based Buffer Overflow

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED8.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary8.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Freebsd Freebsd 14.3 - All All
Operating System Freebsd Freebsd 14.3 p1 All All
Operating System Freebsd Freebsd 14.3 p10 All All
Operating System Freebsd Freebsd 14.3 p11 All All
Operating System Freebsd Freebsd 14.3 p12 All All
Operating System Freebsd Freebsd 14.3 p13 All All
Operating System Freebsd Freebsd 14.3 p2 All All
Operating System Freebsd Freebsd 14.3 p3 All All
Operating System Freebsd Freebsd 14.3 p4 All All
Operating System Freebsd Freebsd 14.3 p5 All All
Operating System Freebsd Freebsd 14.3 p6 All All
Operating System Freebsd Freebsd 14.3 p7 All All
Operating System Freebsd Freebsd 14.3 p8 All All
Operating System Freebsd Freebsd 14.3 p9 All All
Operating System Freebsd Freebsd 14.4 - All All
Operating System Freebsd Freebsd 14.4 p1 All All
Operating System Freebsd Freebsd 14.4 p2 All All
Operating System Freebsd Freebsd 14.4 p3 All All
Operating System Freebsd Freebsd 14.4 p4 All All
Operating System Freebsd Freebsd 14.4 rc1 All All
Operating System Freebsd Freebsd 15.0 - All All
Operating System Freebsd Freebsd 15.0 p1 All All
Operating System Freebsd Freebsd 15.0 p2 All All
Operating System Freebsd Freebsd 15.0 p3 All All
Operating System Freebsd Freebsd 15.0 p4 All All
Operating System Freebsd Freebsd 15.0 p5 All All
Operating System Freebsd Freebsd 15.0 p6 All All
Operating System Freebsd Freebsd 15.0 p7 All All
Operating System Freebsd Freebsd 15.0 p8 All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA FreeBSD FreeBSD affected 15.0-RELEASE p9 release Not specified
CNA FreeBSD FreeBSD affected 14.4-RELEASE p5 release Not specified
CNA FreeBSD FreeBSD affected 14.3-RELEASE p14 release Not specified

References

ReferenceSourceLinkTags
security.freebsd.org/advisories/FreeBSD-SA-26:22.libcasper.asc [email protected] security.freebsd.org Vendor Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Joshua Rogers of AISLE Research Team (en)

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