A vulnerability in the XAR file format parser of ClamAV could allow an unauthenticated, remote attacker to cause a DoS condition or possibly other expanded impacts as a result of memory corruption on an affected device. This vulnerability is due to improper boundary checks for content in XAR files during scanning. An attacker could exploit this vulnerability by submitting a crafted file that contains XAR content to be scanned by ClamAV on an affected device. A successful exploit could allow the attacker to cause the ClamAV scanning process to terminate, resulting in a DoS condition on the affected software.

A vulnerability in the GPT file format parser of ClamAV could allow an unauthenticated, remote attacker to cause a DoS condition or possibly other expanded impacts as a result of memory corruption on an affected device. This vulnerability is due to improper handling of an endian conversion operation, which may result in an out-of-bounds buffer write. An attacker could exploit this vulnerability by submitting a crafted GPT file to be scanned by ClamAV on an affected device. A successful exploit could allow the attacker to cause the ClamAV scanning process to terminate, resulting in a DoS condition on the affected software.

A vulnerability in the PESpin file format parser of ClamAV could allow an unauthenticated, remote attacker to cause a DoS condition or possibly other expanded impacts as a result of memory corruption on an affected device. This vulnerability is due to improper boundary checks for content in PESpin files during scanning, which may result in an integer overflow. An attacker could exploit this vulnerability by submitting a crafted file that contains PESpin content to be scanned by ClamAV on an affected device. A successful exploit could allow the attacker to cause the ClamAV scanning process to terminate, resulting in a DoS condition on the affected software.

A vulnerability in the Mach-O file format parser of ClamAV could allow an unauthenticated, remote attacker to cause a DoS condition or possibly other expanded impacts as a result of memory corruption on an affected device. This vulnerability is due to improper boundary checks for content in Mach-O files during scanning, which may result in an out-of-bounds buffer read. An attacker could exploit this vulnerability by submitting a crafted Mach-O file to be scanned by ClamAV on an affected device. A successful exploit could allow the attacker to cause the ClamAV scanning process to terminate, resulting in a DoS condition on the affected software.

A vulnerability in the zip archive parser of ClamAV could allow an unauthenticated, remote attacker to cause a DoS condition on an affected device. This vulnerability is due to improper memory handling when processing content in zip files during scanning. An attacker could exploit this vulnerability by submitting a crafted zip file for scanning. A successful exploit could allow the attacker to cause the ClamAV scanning process to terminate as a result of a memory double-free, resulting in a DoS condition on the affected software.

A vulnerability in the zip archive parser of ClamAV could allow an unauthenticated, remote attacker to cause a DoS condition on an affected device. This vulnerability is due to improper boundary checks for content in zip files during scanning, which may result in an out-of-bounds write condition. An attacker could exploit this vulnerability by submitting a crafted zip file for scanning. A successful exploit could allow the attacker to cause the ClamAV scanning process to terminate, resulting in a DoS condition on the affected software.

A vulnerability in the ALZ file format parser of ClamAV could allow an unauthenticated, remote attacker to cause a DoS condition, or possibly other expanded impacts, resulting from memory corruption on an affected device.

A vulnerability in the DMG file format parser of ClamAV could allow an unauthenticated, remote attacker to cause a DoS condition, or possibly other expanded impacts, resulting from memory corruption on an affected device.

A vulnerability in the 7z file format parser of ClamAV could allow an unauthenticated, remote attacker to cause a DoS condition, or possibly other expanded impacts, resulting from memory corruption on an affected device.

A vulnerability in the PESpin file format parser of ClamAV could allow an unauthenticated, remote attacker to cause a DoS condition, or possibly other expanded impacts, resulting from memory corruption on an affected device.

A vulnerability in the InstallShield file format parser of ClamAV could allow an unauthenticated, remote attacker to cause a DoS condition on an affected device.

A vulnerability in the PE file format parser of ClamAV could allow an unauthenticated, remote attacker to cause a DoS condition, or possibly other expanded impacts, resulting from memory corruption on an affected device.

A vulnerability in the FSG file format parser of ClamAV could allow an unauthenticated, remote attacker to cause a DoS condition, or possibly other expanded impacts, resulting from memory corruption on an affected device.

On July 1, 2026, the Cisco Product Security Incident Response Team (PSIRT) published the following advisories:Cisco Security AdvisoryCVE-IDSecurity Impact RatingCVSS Base ScoreCisco Catalyst Center Arbitrary File Read VulnerabilityCVE-2026-20191High7.5ClamAV Vulnerabilities Affecting Cisco Products: July 2026CVE-2026-20216CVE-2026-20213CVE-2026-20214CVE-2026-20215CVE-2026-20217CVE-2026-20243CVE-2026-20244High7.5To fully remediate the vulnerabilities that were disclosed on July 1, 2026, Cisco strongly recommends that customers upgrade to the fixed software that is indicated in the advisories.For more information about changes in Cisco PSIRT vulnerability disclosure, see Strengthening the Foundation: A Predictable, Customer-Focused Response to AI-Accelerated Vulnerability Discovery.

ClamAV versions prior to 0.103.0-rc contain a vulnerability in function name processing through the ClamBC bytecode interpreter that allows attackers to manipulate bytecode function names. Attackers can exploit the weak input validation in function name encoding to potentially execute malicious bytecode or cause unexpected behavior in the ClamAV engine.

This vulnerability allows remote attackers to disclose sensitive information on affected installations of Clam AntiVirus. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The ZDI has assigned a CVSS rating of 6.1. The following CVEs are assigned: CVE-2025-20234.

https://blog.clamav.net/2025/06/clamav-143-and-109-security-patch.html announces: Today, we are publishing the 1.4.3 and 1.0.9 security patch versions.

[....]

CVE-2025-20260: Fixed a possible buffer overflow write bug in the PDF file parser that could cause a denial-of-service (DoS) condition or enable remote code execution.

This issue only affects configurations where both:

The max file-size scan limit is set greater than or equal to 1024MB. The max scan-size scan limit is set greater than or equal to 1025MB.

The code flaw was present prior to version 1.0.0, but a change in version 1.0.0 that enables larger allocations based on untrusted data made it possible to trigger this bug.

This issue affects all currently supported versions. It will be fixed in:

1.4.3 1.0.9

Thank you to Greg Walkup at Sandia National Labs for identifying this issue.

CVE-2025-20234: Fixed a possible buffer overflow read bug in the UDF file parser that may write to a temp file and thus disclose information, or it may crash and cause a denial-of-service (DoS) condition.

This issue was introduced in version 1.2.0. It will be fixed in 1.4.3.

Thank you to volticks (@movx64 on Twitter/X), working with Trend Micro Zero Day Initiative, for identifying this issue.

Fixed a possible use-after-free bug in the Xz decompression module in the bundled lzma-sdk library.

This issue was fixed in the lzma-sdk version 18.03. ClamAV bundles a copy of the lzma-sdk with some performance changes specific to libclamav, plus select bug fixes like this one in lieu of a full upgrade to newer lzma-sdk.

This issue affects all ClamAV versions at least as far back as 0.99.4. It will be fixed in:

1.4.3 1.0.9

Thank you to OSS-Fuzz for identifying this issue. -- -Alan Coopersmith- alan.coopersmith () oracle com Oracle Solaris Engineering - https://blogs.oracle.com/solaris

A vulnerability in the PDF scanning processes of ClamAV could allow an unauthenticated, remote attacker to cause a buffer overflow condition, cause a denial of service (DoS) condition, or execute arbitrary code on an affected device. This vulnerability exists because memory buffers are allocated incorrectly when PDF files are processed. An attacker could exploit this vulnerability by submitting a crafted PDF file to be scanned by ClamAV on an affected device. A successful exploit could allow the attacker to trigger a buffer overflow, likely resulting in the termination of the ClamAV scanning process and a DoS condition on the affected software. Although unproven, there is also a possibility that an attacker could leverage the buffer overflow to execute arbitrary code with the privileges of the ClamAV process.

A vulnerability in Universal Disk Format (UDF) processing of ClamAV could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to a memory overread during UDF file scanning. An attacker could exploit this vulnerability by submitting a crafted file containing UDF content to be scanned by ClamAV on an affected device. A successful exploit could allow the attacker to terminate the ClamAV scanning process, resulting in a DoS condition on the affected software. For a description of this vulnerability, see the .

A vulnerability in the Object Linking and Embedding 2 (OLE2) decryption routine of ClamAV could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to an integer underflow in a bounds check that allows for a heap buffer overflow read. An attacker could exploit this vulnerability by submitting a crafted file containing OLE2 content to be scanned by ClamAV on an affected device. A successful exploit could allow the attacker to terminate the ClamAV scanning process, resulting in a DoS condition on the affected software. For a description of this vulnerability, see the . Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

A vulnerability in the Object Linking and Embedding 2 (OLE2) decryption routine of ClamAV could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.This vulnerability is due to an integer underflow in a bounds check that allows for a heap buffer overflow read. An attacker could exploit this vulnerability by submitting a crafted file containing OLE2 content to be scanned by ClamAV on an affected device. A successful exploit could allow the attacker to terminate the ClamAV scanning process, resulting in a DoS condition on the affected software.For a description of this vulnerability, see the ClamAV blog.Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.This advisory is available at the following link:https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-clamav-ole2-H549rphA

A vulnerability in the ClamD service module of Clam AntiVirus (ClamAV) versions 1.4.0, 1.3.2 and prior versions, all 1.2.x versions, 1.0.6 and prior versions, all 0.105.x versions, all 0.104.x versions, and 0.103.11 and all prior versions could allow an authenticated, local attacker to corrupt critical system files. The vulnerability is due to allowing the ClamD process to write to its log file while privileged without checking if the logfile has been replaced with a symbolic link. An attacker could exploit this vulnerability if they replace the ClamD log file with a symlink to a critical system file and then find a way to restart the ClamD process. An exploit could allow the attacker to corrupt a critical system file by appending ClamD log messages after restart.

A vulnerability in the PDF parsing module of Clam AntiVirus (ClamAV) versions 1.4.0, 1.3.2 and prior versions, all 1.2.x versions, 1.0.6 and prior versions, all 0.105.x versions, all 0.104.x versions, and 0.103.11 and all prior versions could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to an out of bounds read. An attacker could exploit this vulnerability by submitting a crafted PDF file to be scanned by ClamAV on an affected device. An exploit could allow the attacker to terminate the scanning process.

A vulnerability in the HTML parser of ClamAV could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to an issue in the C to Rust foreign function interface. An attacker could exploit this vulnerability by submitting a crafted file containing HTML content to be scanned by ClamAV on an affected device. An exploit could allow the attacker to cause the ClamAV scanning process to terminate, resulting in a DoS condition on the affected software.

A vulnerability in the VirusEvent feature of ClamAV could allow a local attacker to inject arbitrary commands with the privileges of the application service account.The vulnerability is due to unsafe handling of file names. A local attacker could exploit this vulnerability by supplying a file name containing command-line sequences. When processed on a system using configuration options for the VirusEvent feature, the attacker could cause the application to execute arbitrary commands. ClamAV has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

A vulnerability in the OLE2 file format parser of ClamAV could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.This vulnerability is due to an incorrect check for end-of-string values during scanning, which may result in a

A vulnerability in the OLE2 file parser of Clam AntiVirus (ClamAV) versions 0.104.0 through 0.104.2 could allow an unauthenticated, remote attacker to cause a denial of service condition on an affected device.The vulnerability is due to incorrect use of the realloc function that may result in a double-free. An attacker could exploit this vulnerability by submitting a crafted OLE2 file to be scanned by ClamAV on the affected device. An exploit could allow the attacker to cause the ClamAV scanning process to crash, resulting in a denial of service condition.

On Feb 15, 2023, the following vulnerability in the ClamAV scanning library was disclosed: A vulnerability in the DMG file parser of ClamAV versions 1.0.0 and earlier, 0.105.1 and earlier, and 0.103.7 and earlier could allow an unauthenticated, remote attacker to access sensitive information on an affected device. This vulnerability is due to enabling XML entity substitution that may result in XML external entity injection. An attacker could exploit this vulnerability by submitting a crafted DMG file to be scanned by ClamAV on an affected device. A successful exploit could allow the attacker to leak bytes from any file that may be read by the ClamAV scanning process.

On Feb 15, 2023, the following vulnerability in the ClamAV scanning library was disclosed: A vulnerability in the HFS+ partition file parser of ClamAV versions 1.0.0 and earlier, 0.105.1 and earlier, and 0.103.7 and earlier could allow an unauthenticated, remote attacker to execute arbitrary code. This vulnerability is due to a missing buffer size check that may result in a heap buffer overflow write. An attacker could exploit this vulnerability by submitting a crafted HFS+ partition file to be scanned by ClamAV on an affected device. A successful exploit could allow the attacker to execute arbitrary code with the privileges of the ClamAV scanning process, or else crash the process, resulting in a denial of service (DoS) condition. For a description of this vulnerability, see the ClamAV blog ["https://blog.clamav.net/"].

A vulnerability in the regex module used by the signature database load module of Clam AntiVirus (ClamAV) versions 0.104.0 through 0.104.2 and LTS version 0.103.5 and prior versions could allow an authenticated, local attacker to crash ClamAV at database load time, and possibly gain code execution. The vulnerability is due to improper bounds checking that may result in a multi-byte heap buffer overwflow write. An attacker could exploit this vulnerability by placing a crafted CDB ClamAV signature database file in the ClamAV database directory. An exploit could allow the attacker to run code as the clamav user.