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Vulnerabilities

Vulnerability · CVE-2026-39457

When exchanging data over a socket, libnv uses select(2) to wait for data to arrive.

Published Apr 30, 2026 · catalog updated Jun 17, 2026 · When exchanging data over

Check if you run it

No confirmed exploitation is on record for CVE-2026-39457. EPSS is 0.16%. Act only if a listed version of When exchanging data over is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (When exchanging data over).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.8
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.16%
Remediation
Advisory link
Affected products
cpe freebsd/freebsd

When exchanging data over a socket, libnv uses select(2) to wait for data to arrive. However, it does not verify whether the provided socket descriptor fits in select(2)'s file descriptor set size limit of FD_SETSIZE (1024). An attacker who is able to force a libnv application to allocate large file descriptors, e.g., by opening many descriptors and executing a program which is not careful to close them upon startup, can trigger stack corruption. If the target application is setuid-root, then this could be used to elevate local privileges.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe freebsd/freebsd13.5

How to fix CVE-2026-39457

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-39457. EPSS is 0.16%. Act only if a listed version of When exchanging data over is installed.

Which versions are affected?

Compare what you have installed with 13.5. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-121: Stack-based Buffer Overflow. EPSS 0.16%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 30, 2026 · NIST NVD

    Detected

    When exchanging data over a socket, libnv uses select(2) to wait for data to arrive. However, it does not verify whether the provided socket descriptor fits in select(2)'s file descriptor set size limit of FD_SETSIZE (1024). An attacker who is able to force a libnv application to allocate large file descriptors, e.g., by opening many descriptors and executing a program which is not careful to clos

  2. Jun 17, 2026 · NIST NVD

    Updated

    When exchanging data over a socket, libnv uses select(2) to wait for data to arrive. However, it does not verify whether the provided socket descriptor fits in select(2)'s file descriptor set size limit of FD_SETSIZE (1024). An attacker who is able to force a libnv application to allocate large file descriptors, e.g., by opening many descriptors and executing a program which is not careful to clos

Sources

  • CVE.orgVulnerability recordCVE-2026-39457

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-39457

    30-day exploitation probability 0.2%

    first.org
  • NIST NVDVulnerability recordCVE-2026-39457

    When exchanging data over a socket, libnv uses select(2) to wait for data to arrive. However, it does not verify whether the provided socket descriptor fits in select(2)'s file descriptor set size limit of FD_SETSIZE (1024). An attacker who is able to force a libnv application

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.