Security readout for executives and security teams
Plain-English summary
Binwalk versions 2.3.0 through 2.3.2 can follow symlinks during archive extraction. If someone processes a malicious archive or firmware image, files may be read, modified, or disrupted with limited impact. The known fix is upgrading to binwalk 2.3.3.
Executive priority
Treat as a targeted hygiene fix for teams handling untrusted firmware or archives. It is not KEV-listed and has medium severity, but exposed automated analysis pipelines should be updated promptly because the fix is available.
Technical view
CVE-2021-4287 is a CWE-61 symlink-following flaw in ReFirm Labs binwalk's Archive Extraction Handler, specifically extractor.py. The CVSS 3.1 score is 5.0, with network attack vector, high complexity, no privileges required, and required user interaction. Sources identify patch commit fa0c0bd59b8588814756942fe4cb5452e76c1dcd and release v2.3.3.
Likely exposure
Exposure is most likely on security research, firmware analysis, CI, or automated intake systems using binwalk 2.3.0, 2.3.1, or 2.3.2 to extract untrusted archives.
Exploitation context
The source says remote attack is possible, but user interaction is required. No provided source or KEV status supports active exploitation. Practical risk depends on whether vulnerable binwalk instances process files supplied by external or untrusted parties.
Researcher notes
Focus validation on binwalk's archive extraction use, not merely package presence. The cited record does not identify a specific exploit technique beyond symlink following, and this analysis should not assume exploitation or broader product impact without additional evidence.
Mitigation direction
- Upgrade affected binwalk installations to version 2.3.3 or later.
- Prioritize systems that extract untrusted archives or firmware images.
- Pause vulnerable automated extraction workflows until upgraded.
- Check vendor release and patch references for implementation details.
Validation and detection
- Inventory binwalk versions across workstations, containers, CI jobs, and analysis servers.
- Confirm no remaining installations run versions 2.3.0, 2.3.1, or 2.3.2.
- Identify workflows where external files are passed to binwalk extraction.
- Document any delayed upgrades with owner, scope, and target date.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-61: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-4287 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L1.63.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5MediumVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L
Source materials
- CVE List V5 sourceCVE List V5
- https://vuldb.com/?id.216876CVE reference · vdb-entry
- https://vuldb.com/?ctiid.216876CVE reference · signature, permissions-required
- https://github.com/ReFirmLabs/binwalk/pull/556CVE reference · issue-tracking
- https://github.com/ReFirmLabs/binwalk/commit/fa0c0bd59b8588814756942fe4cb5452e76c1dcdCVE reference · patch
- https://github.com/ReFirmLabs/binwalk/releases/tag/v2.3.3CVE reference · patch
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
UNIX Symbolic Link (Symlink) Following
UNIX Symbolic Link (Symlink) Following represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.