Remote inspection-engine restart via malformed mDNS fields
Published Mar 4, 2026 · Updated Mar 4, 2026
Out-of-bounds write in affected Cisco security products allows remote attackers to restart Snort 3 inspection with crafted HTTP packets. The HTTP inspector incompletely checks errors while parsing Multicast DNS fields in an HTTP header, allowing malformed field data to reach an out-of-bounds write. The packets must traverse an established connection and reach an active Snort 3 engine; exploitation restarts only that engine and interrupts packet inspection.
Summary
What happened
Out-of-bounds write in affected Cisco security products allows remote attackers to restart Snort 3 inspection with crafted HTTP packets. The HTTP inspector incompletely checks errors while parsing Multicast DNS fields in an HTTP header, allowing malformed field data to reach an out-of-bounds write. The packets must traverse an established connection and reach an active Snort 3 engine; exploitation restarts only that engine and interrupts packet inspection.
The record
- CVE
- CVE-2026-20067
- Published
- Mar 4, 2026
- Updated
- Mar 4, 2026
- Vendor
- ClamAV
- Product
- Cisco Cyber Vision
- Classifications
- CWE-787, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 4, 2026CVE publishedPublication date reported by the CVE source.
- Mar 4, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=3.0.0
- Affected versionversion=3.0.1
- Affected versionversion=3.0.2
- Affected versionversion=3.0.3
- Affected versionversion=3.0.4
- Affected versionversion=3.0.5
- Affected versionversion=3.0.6
- Affected versionversion=3.1.0
- Affected versionversion=3.1.1
- Affected versionversion=3.1.2
- Affected versionversion=3.2.0
- Affected versionversion=3.2.1
- Affected versionversion=3.2.2
- Affected versionversion=3.2.3
- Affected versionversion=3.2.4
- Affected versionversion=4.0.0
- Affected versionversion=4.0.1
- Affected versionversion=4.0.2
- Affected versionversion=4.0.3
- Affected versionversion=4.1.0
- Affected versionversion=4.1.1
- Affected versionversion=4.1.2
- Affected versionversion=4.1.3
- Affected versionversion=4.1.4
- Affected versionversion=4.1.5
- Affected versionversion=4.1.6
- Affected versionversion=4.1.7
- Affected versionversion=4.2.0
- Affected versionversion=4.2.1
- Affected versionversion=4.2.2
- Affected versionversion=4.2.3
- Affected versionversion=4.2.4
- Affected versionversion=4.2.6
- Affected versionversion=4.2.X
- Affected versionversion=4.3.0
- Affected versionversion=4.3.1
- Affected versionversion=4.3.2
- Affected versionversion=4.3.3
- Affected versionversion=4.4.0
- Affected versionversion=4.4.1
- Affected versionversion=4.4.2
- Affected versionversion=4.4.3
- Affected versionversion=5.0.0
- Affected versionversion=5.0.1
- Affected versionversion=5.0.2
- Affected versionversion=5.1.0
- Affected versionversion=5.1.1
- Affected versionversion=5.1.2
- Affected versionversion=5.1.3
- Affected versionversion=5.2.0
- Affected versionversion=5.2.1
- Affected versionversion=5.3.0
- Affected versionversion=5.3.1
- Affected versionversion=5.3.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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