CVE-2026-20056 | Cisco Secure Web Appliance TBD Bypass Vulnerability

A vulnerability in the Dynamic Vectoring and Streaming (DVS) Engine implementation of Cisco AsyncOS Software for Cisco Secure Web Appliance could allow an unauthenticated, remote attacker to bypass the anti-malware scanner, allowing malicious archive files to be downloaded. This vulnerability is due to improper handling of certain archive files. An attacker could exploit this vulnerability by sending a crafted archive file, which should be blocked, through an affected device. A successful exploit could allow the attacker to bypass the anti-malware scanner and download malware onto an end user workstation. The downloaded malware will not automatically execute unless the end user extracts and launches the malicious file. 

Published: 2026-02-04 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2026-20056 is rated Low Risk (17.4/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.14%). Mandatory action: Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-20056

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.01% 0.14% +0.12%
2 2026-02-05 0.01%

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-20056

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
4.0 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
2.2 1.4 [email protected]

Weakness enumeration for CVE-2026-20056

Affected software / configurations for CVE-2026-20056

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-20056

cvelogic Threat Intelligence