CVE-2026-42301
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedpyp2spec generates working Fedora RPM spec file for Python projects. Prior to version 0.14.1, pyp2spec was writing PyPI package metadata (e.g. the summary field) into the generated spec file without escaping RPM macro directives. When a packager then runs rpmbuild, those directives get evaluated, so a malicious package can execute arbitrary commands on the build machine. This issue has been patched in version 0.14.1.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidencepyp2spec generates Fedora RPM spec files for Python projects. Prior to version 0.14.1, the tool wrote PyPI package metadata (such as the summary field) into generated spec files without escaping RPM macro directives. When rpmbuild processes these spec files, the unescaped macros are evaluated, allowing a malicious package to inject and execute arbitrary commands on the build machine.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check if pyp2spec is installedRun: pip show pyp2spec or pip3 show pyp2specAffected if pyp2spec is not installed or the version field shows a version lower than 0.14.1
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Verify the installed version numberRun: pip show pyp2spec | grep Version or pip3 list | grep pyp2specAffected if The version displayed is prior to 0.14.1 (e.g., 0.14.0, 0.13.x, etc.)
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Identify generated spec filesSearch for .spec files in the system: find /home -name '*.spec' 2>/dev/null, or check common working directories for spec file generationAffected if Spec files exist that were generated using the vulnerable pyp2spec version
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Inspect metadata fields in spec filesOpen a generated .spec file and examine the Summary, Description, or other metadata fields for unescaped RPM macro characters (%, {, })Affected if The Summary or other metadata fields contain raw % characters that could be interpreted as RPM macros (e.g., %summary, %{python_module})
You are affected if pyp2spec version is below 0.14.1 AND you have generated spec files from PyPI packages using this version, as unescaped macro characters in metadata fields could allow command injection during rpmbuild.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scopedUpgrade pyp2spec to version 0.14.1 or later to patch the macro injection vulnerability. Review any existing spec files generated by earlier versions for potentially malicious macros before building.
0.14.1
- Upgrade pyp2spec to version 0.14.1 or later to resolve the command injection vulnerability
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation1.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,376.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-42301 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-42301 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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