CVE-2025-7207Public exploit

Local runtime crash via uninitialized register count

Published Jul 9, 2025 · Updated Jul 9, 2025

Heap-based buffer overflow in mruby 3.4.0-rc1 and 3.4.0-rc2 allows local users to crash the runtime with crafted Ruby source. scope_new initializes nlocals from the scope stack pointer but leaves nregs unset, allowing VM stack_clear to write past the allocated stack. A local user or embedding application must cause the compiler to process the crafted source; demonstrated impact is an AddressSanitizer-detected abort.

CVSS severity5.5
Medium
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Heap-based buffer overflow in mruby 3.4.0-rc1 and 3.4.0-rc2 allows local users to crash the runtime with crafted Ruby source. scope_new initializes nlocals from the scope stack pointer but leaves nregs unset, allowing VM stack_clear to write past the allocated stack. A local user or embedding application must cause the compiler to process the crafted source; demonstrated impact is an AddressSanitizer-detected abort.

The record

CVE
CVE-2025-7207
Published
Jul 9, 2025
Updated
Jul 9, 2025
Vendor
mruby
Product
mruby
Classifications
CWE-787, CWE-122, CWE-119, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 9, 2025CVE publishedPublication date reported by the CVE source.
  2. Jul 9, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=3.4.0-rc1
  2. Affected versionversion=3.4.0-rc2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

mruby · mrubyversion=3.4.0-rc1; version=3.4.0-rc2

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
1.7VulDBAV:L/AC:L/Au:S/C:N/I:N/A:P
3.3VulDBCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
1.9VulDBCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
CWE-122Heap-based Buffer Overflow
CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
T1499Endpoint Denial of Service

Public exploit references

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

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo