Security readout for executives and security teams
Plain-English summary
ClamAV 0.103.0 and 0.103.1 can be crashed by a crafted PDF during scanning. The business impact is availability: email or file scanning may fail, queue, or stop protecting dependent workflows. Sources do not show active exploitation.
Executive priority
Treat this as a high-priority availability fix for systems that depend on ClamAV scanning. It is not described as data theft or code execution, but scanner crashes can disrupt mail, upload, or security workflows.
Technical view
The issue is in ClamAV's PDF parsing module. Improper buffer size tracking can cause a heap buffer over-read when processing a crafted PDF, crashing the scanning process. It is rated CVSS 3.1 7.5 with network attack vector, no privileges, no user interaction, and high availability impact.
Likely exposure
Exposure is most likely where ClamAV 0.103.0 or 0.103.1 scans untrusted PDFs, including mail gateways, attachment scanners, file-upload pipelines, and backend malware scanning services.
Exploitation context
The source bundle describes unauthenticated remote triggering by sending a crafted PDF to an affected device. KEV is false, and no provided source states active exploitation or public weaponization.
Researcher notes
Evidence is limited to the CVE record and the vendor patch reference. The affected versions are ClamAV 0.103.0 and 0.103.1. The root cause is CWE-20 improper input validation leading to heap buffer over-read in PDF parsing.
Mitigation direction
- Inventory ClamAV deployments and identify versions 0.103.0 and 0.103.1.
- Review the ClamAV 0.103.2 security patch release guidance.
- Upgrade affected ClamAV instances away from vulnerable versions.
- Monitor scanning services for crashes, failed scans, and queued mail or files.
- Prioritize exposed systems that process untrusted PDFs.
Validation and detection
- Confirm the installed ClamAV version on every scanner node.
- Map where ClamAV receives inbound email attachments or uploaded PDFs.
- Check service logs for scanner crashes during PDF processing.
- Verify updated scanners remain stable under normal PDF scanning workloads.
- Confirm operational runbooks cover scanner crash alerts and queue growth.
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-20: 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-2021-1404 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
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://blog.clamav.net/2021/04/clamav-01032-security-patch-release.htmlCVE reference · vendor-advisory, x_refsource_CISCO
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.
Improper Input Validation
Improper Input Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.