GHSA-4c3c-r6p8-c863
GHSA-4c3c-r6p8-c863 is a CWE-74 vulnerability in flawfinder. O3 Security confirms whether GHSA-4c3c-r6p8-c863 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Flawfinder output manipulation via untrusted filenames and source text
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-4c3c-r6p8-c863.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
flawfinderReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Impact
This vulnerability is an improper input neutralization issue leading to output manipulation, specifically, Terminal/ANSI Escape Sequence Injection and XML Injection:
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Terminal Output Spoofing: A malicious file whose name contains ANSI escape sequences can end up being included in flawfinder's standard terminal output, with many effects. For example, this might allow an attacker to hide critical scan results, falsely making it appear to a human reviewer that no security issues were found.
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CSV and XML Injection: Untrusted fields (such as filenames, categories, or code context text) were not properly sanitized when generating structured reports. An attacker could exploit this to corrupt CSV formats or inject arbitrary XML attributes into SonarQube outputs via output_sonar().
It impacts those who use flawfinder to evaluate intentionally malicious filenames or file contents.
The initial filename injection problem was reported by Dan Lenz https://www.linkedin.com/in/dan-lenz/
The other vulnerabilities were found by flawfinder project leader David A. Wheeler, GitHub david-a-wheeler, https://dwheeler.com/
Patches
This issue has been fully patched in Version 2.0.20 (released 2026-05-16). All users should upgrade to version 2.0.20 or later immediately. If you use Python's package manager, you can upgrade using pip install --upgrade flawfinder. If you are consuming flawfinder via GitHub Actions, ensure your workflow points to david-a-wheeler/[email protected] or later.
Workarounds
There is no configuration-based workaround within older versions of flawfinder. If an immediate upgrade is not possible, users can mitigate the risk by:
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Pre-scanning filenames: Manually or programmatically verifying that target repositories do not contain filenames with control characters (including ANSI escape sequences) before passing them to flawfinder.
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Inspecting raw output: Reviewing flawfinder outputs in a text editor or logging mechanism that explicitly displays or strips raw escape sequences, rather than relying on live terminal rendering.
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Restricting untrusted inputs: Avoiding the generation of SonarQube or CSV reports from completely untrusted repositories until the tool is updated.
Resources
See the flawfinder GitHub Repository: https://github.com/david-a-wheeler/flawfinder
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | flawfinder | all versions | 2.0.20 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for flawfinder. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update flawfinder to 2.0.20 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4c3c-r6p8-c863 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-4c3c-r6p8-c863 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-4c3c-r6p8-c863. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-4c3c-r6p8-c863 in your dependencies?
O3 detects GHSA-4c3c-r6p8-c863 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.