Flawfinder output manipulation via untrusted filenames and source text

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

8.7 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-48813: 0.44% estimated exploitation activity in the next 30 days; percentile 38.64 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact This vulnerability is an improper input neutralization issue leading to output manipulation, specifically, Terminal/ANSI Escape Sequence Injection and XML Injection: 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. 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 outputsonar(). 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…

Published by the source

26 Jun 2026, 20:52 UTC

Last modified by the source

11 Aug 2026, 19:30 UTC

Source last checked

26 Oct 2026, 13:50 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-4c3c-r6p8-c863

2. Revision 2 · amended · 25 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-4c3c-r6p8-c863

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-48813

Advisory: Flawfinder output manipulation via untrusted filenames and source text
IDs: CVE-2026-48813, GHSA-4c3c-r6p8-c863
Record: https://patchnext.com/advisories/cve-2026-48813 (revision 3, source checked 26 Oct 2026, 13:50 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: flawfinder 2.0.20. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI flawfinder: affected < 2.0.20; fixed in 2.0.20

## Suggested inspection (read-only)
- `python -m pip show flawfinder`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on flawfinder.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-4c3c-r6p8-c863 (OSV record GHSA-4c3c-r6p8-c863 lists affected ranges: PyPI flawfinder >=0 <2.0.20 (fixed))
- Verified: https://github.com/advisories/GHSA-4c3c-r6p8-c863 (GitHub-reviewed advisory GHSA-4c3c-r6p8-c863 lists affected ranges: PyPI flawfinder >=0 <2.0.20)

Commands are suggestions: review each one before running it.