The Microsoft CHM file parser in ClamAV 0.96.4 and Sophos Anti-Virus 4.61.0 allows remote attackers to bypass malware detection via a crafte
The Microsoft CHM file parser in ClamAV 0.96.4 and Sophos Anti-Virus 4.61.0 allows remote attackers to bypass malware detection via a crafted reset interval in the LZXC header of a CHM file. NOTE: this may later be SPLIT into multiple CVEs if additional information is published showing that the error occurred independently in different CHM parser implementations.
- Published
- Mar 21, 2012
- Updated
- Jun 16, 2026
- EPSS
- 73.7% · 99th percentile
- CWE
- CWE-264
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Report tools
Action score
39
Monitor
Low priority for now.
- CVSS
- 17 / 40 · 4.3 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 22 / 30 · 73.7%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| clamav | clamav | cpe:2.3:a:clamav:clamav |
| sophos | sophos anti-virus | cpe:2.3:a:sophos:sophos_anti-virus |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- clamav clamav0.96.4
- sophos sophos anti-virus4.61.0
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | clamav | before 0.97.5+dfsg-1 | 0.97.5+dfsg-1 |
| openSUSE:Tumbleweed | clamav | before 0.99.2-4.1 | 0.99.2-4.1 |
Same product
clamav: all recordsOther highest-scoring records for the same primary product.
- CVE-2023-20032On Feb 15, 2023, the following vulnerability in the ClamAV scanning library was disclosed:
A vulnerability in the HFS+ partition file p48Plan
- CVE-2024-20328ClamAV VirusEvent File Processing Command Injection Vulnerability46Plan
- CVE-2017-12379ClamAV AntiVirus software versions 0.99.2 and prior contain a vulnerability that could allow an unauthenticated, remote attacker to cause a 43Plan
- CVE-2006-1615Multiple format string vulnerabilities in the logging code in Clam AntiVirus (ClamAV) before 0.88.1 might allow remote attackers to execute 43Plan
- CVE-2017-12377ClamAV AntiVirus software versions 0.99.2 and prior contain a vulnerability that could allow an unauthenticated, remote attacker to cause a 42Plan
- CVE-2009-1372Stack-based buffer overflow in the cli_url_canon function in libclamav/phishcheck.c in ClamAV before 0.95.1 allows remote attackers to cause42Plan
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:clamav | 0.97.5+dfsg-1 · Debian:12 | Package registry (OSV) |
| opensuse:clamav | 0.99.2-4.1 · openSUSE:Tumbleweed | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.
Technical details
Attack conditions
If successful
- Confidentiality
- none
- Integrity
- P · data or configuration can be modified
- Availability
- none
- Attack complexity
- M
- Confidentiality impact
- None
- Integrity impact
- P
- Availability impact
- None
Weakness class (CWE)
CWE-264 · Permissions, Privileges, and Access ControlsCVSS vector
AV:N/AC:M/Au:N/C:N/I:P/A:N
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- lists.opensuse.org/opensuse-security-announce/2012-07/msg00002.html
- osvdb.org/80473
- osvdb.org/80474
- www.ieee-security.org/TC/SP2012/program.html
- www.mandriva.com/security/advisories?name=MDVSA-2012:094
- www.securityfocus.com/archive/1/522005
- www.securityfocus.com/bid/52611
- exchange.xforce.ibmcloud.com/vulnerabilities/74301
Vendor advisories and official records. Exploit/PoC links are deliberately left out.