Security readout for executives and security teams
Plain-English summary
CVE-2020-21427 is a high-severity memory corruption flaw in FreeImage 3.18.0. A crafted BMP image can trigger a buffer overflow when FreeImage decodes RLE8 pixel data, potentially allowing code execution or service disruption if the file is processed.
Executive priority
Treat this as a high-priority patching and exposure-discovery issue, not confirmed emergency exploitation. Focus first on internet-facing or business-critical systems that process uploaded images.
Technical view
The flaw is reported in LoadPixelDataRLE8 in PluginBMP.cpp and maps to CWE-120. The CVSS 3.1 score is 7.8 with low complexity, no privileges required, user interaction required, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is most likely in applications, services, or Linux packages that use FreeImage 3.18.0 to process BMP images, especially user-supplied files. The CVE affected-product metadata is incomplete, but Debian and Fedora advisories show downstream package exposure.
Exploitation context
The source bundle does not show CISA KEV listing or active exploitation. The reported attack path is a crafted image file, and CVSS marks user interaction as required. Risk rises where automated workflows process untrusted images.
Researcher notes
Evidence supports a buffer overflow in FreeImage BMP RLE8 decoding, but the bundle lacks a precise upstream fixed version and complete affected CPE data. Avoid assuming exploit availability beyond crafted-file triggering described by CVE sources.
Mitigation direction
- Apply Debian or Fedora FreeImage security updates where those packages are used.
- Inventory applications that bundle or statically link FreeImage.
- Check FreeImage project or vendor guidance for source-build fixes.
- Limit or sandbox processing of untrusted BMP files.
- Prioritize systems accepting image uploads or email attachments.
Validation and detection
- Check installed FreeImage package versions on Debian and Fedora systems.
- Review application dependency manifests for FreeImage 3.18.0.
- Identify image-processing paths that accept untrusted BMP files.
- Confirm vendor advisories are mapped to deployed packages.
- Verify patched systems with normal image-processing regression tests.
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-120: 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 lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2020-21427 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
- High
- CVSS
- 7.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
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:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H1.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://sourceforge.net/p/freeimage/bugs/298/CVE reference
- FEDORA-2023-a8b26b910dCVE reference · vendor-advisory
- FEDORA-2023-2840932fa8CVE reference · vendor-advisory
- [debian-lts-announce] 20231125 [SECURITY] [DLA 3662-1] freeimage security updateCVE reference · mailing-list
- DSA-5579CVE reference · vendor-advisory
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.
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.