CVE-2026-42301

Arbitrary command execution via unescaped RPM macros

Published May 9, 2026 · Updated May 9, 2026

Code injection in pyp2spec before 0.14.1 allows attackers to execute arbitrary commands when a packager processes malicious PyPI metadata. The spec generator copies metadata fields such as Summary into an RPM spec without neutralizing macro directives, which RPM evaluates during parsing. Exploitation requires a packager to generate and then inspect or build the crafted spec; any RPM tool that parses it can run the embedded command on the build host.

CVSS severity7.8
High
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code injection in pyp2spec before 0.14.1 allows attackers to execute arbitrary commands when a packager processes malicious PyPI metadata. The spec generator copies metadata fields such as Summary into an RPM spec without neutralizing macro directives, which RPM evaluates during parsing. Exploitation requires a packager to generate and then inspect or build the crafted spec; any RPM tool that parses it can run the embedded command on the build host.

The record

CVE
CVE-2026-42301
Published
May 9, 2026
Updated
May 9, 2026
Vendor
Karolina Surma
Product
pyp2spec
Classifications
CWE-20, CWE-94, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 9, 2026CVE publishedPublication date reported by the CVE source.
  2. May 9, 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?

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

  1. Affected versionversion=< 0.14.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Karolina Surma · pyp2specversion=< 0.14.1

Published CVSS scores

7.8GitHubCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/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.

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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-20Improper Input Validation
CWE-94Improper Control of Generation of Code ('Code Injection')
T1204.002User Execution: Malicious File

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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