CVE-2026-38755

Shell crash via unbounded function recursion

Published Jul 15, 2026 · Updated Jul 15, 2026

Uncontrolled recursion in BusyBox 0.52 through 1.38.0 allows local users to crash the ash shell with a recursive shell function. The evalfun() path repeatedly enters recursive shell functions without tracking call depth, exhausting the process stack instead of rejecting excessive nesting. Exploitation requires local ability to run crafted ash input and interrupts only the affected shell process, with no reported data disclosure or modification.

CVSS severity2.9
Low
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncontrolled recursion in BusyBox 0.52 through 1.38.0 allows local users to crash the ash shell with a recursive shell function. The evalfun() path repeatedly enters recursive shell functions without tracking call depth, exhausting the process stack instead of rejecting excessive nesting. Exploitation requires local ability to run crafted ash input and interrupts only the affected shell process, with no reported data disclosure or modification.

The record

CVE
CVE-2026-38755
Published
Jul 15, 2026
Updated
Jul 15, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-122, CWE-674, T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

2.9MITRECVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.5Red HatCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
CWE-674Uncontrolled Recursion
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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