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Mallory
Medium

DoS in Snort 3 VBA decompression error handling (infinite loop)

IdentifiersCVE-2026-20054CWE-754

Multiple Cisco products are affected by a denial-of-service vulnerability in the Snort 3 Visual Basic for Applications (VBA) feature. The issue is caused by improper error checking when decompressing VBA data. An unauthenticated remote attacker can trigger the flaw by sending crafted VBA data to the Snort 3 Detection Engine, causing the engine to enter an infinite loop and crash, resulting in a DoS condition.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can cause the Snort 3 Detection Engine to enter an infinite loop and crash, resulting in denial of service (loss of inspection/detection functionality and potential traffic handling degradation depending on product integration).

Mitigation

If you can’t patch tonight, do this now.

No specific mitigations are provided in the supplied content beyond updating. As a general compensating control, reduce exposure to untrusted inputs reaching the Snort 3 Detection Engine where feasible (e.g., limit inspection of untrusted traffic paths), but product-specific guidance is not available in the provided material.

Remediation

Patch, then assume compromise.

Apply the vendor-provided Cisco software update/fixed release that addresses CVE-2026-20054 for the affected product(s) and Snort 3 component. (Specific fixed versions are not provided in the supplied content.)
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
Cisco SystemsCyber Visionapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

What this page doesn’t show

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This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.
Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity1

Community discussion across Reddit, Mastodon, and other social sources.