Security readout for executives and security teams
Plain-English summary
Cisco WSA can be forced to stop processing web traffic by an authenticated remote attacker sending specially crafted HTTP or HTTPS requests through the appliance. The business risk is proxy outage and disrupted web access, not data theft, based on the provided sources.
Executive priority
Treat as a high-priority availability issue for environments dependent on Cisco WSA for web access. It does not indicate confidentiality or integrity impact in the provided sources, but a proxy outage can interrupt business operations and user connectivity.
Technical view
CVE-2019-1884 is a CWE-20 input validation flaw in Cisco AsyncOS Software for Cisco Web Security Appliance web proxy handling. With low attack complexity and valid access, a remote attacker can trigger a denial of service that stops traffic processing. CVSS v3.0 is 7.7 high.
Likely exposure
Organizations using Cisco Web Security Appliance as a web proxy are potentially exposed. The bundle does not specify affected AsyncOS versions, so exposure depends on appliance inventory and Cisco advisory applicability.
Exploitation context
The provided sources describe authenticated remote exploitation via malicious HTTP or HTTPS requests through the affected appliance. CISA KEV is false, and no cited source here confirms active exploitation.
Researcher notes
Key constraints are PR:L, AV:N, UI:N, and A:H. The affected version data is not included in the bundle beyond Cisco WSA/AsyncOS, so validation should anchor on Cisco’s advisory and local appliance versions. Avoid assuming exploit-in-the-wild status.
Mitigation direction
- Review Cisco advisory cisco-sa-20190703-asyncos-wsa for affected and fixed releases.
- Identify all Cisco WSA appliances and their AsyncOS versions.
- Apply Cisco-recommended software updates or mitigations where applicable.
- Restrict who can send proxied traffic through WSA where operationally feasible.
- Monitor WSA availability and proxy traffic failures until remediation is complete.
Validation and detection
- Confirm whether Cisco WSA is deployed in the environment.
- Compare AsyncOS versions against Cisco advisory affected-version guidance.
- Check change records for Cisco-recommended updates or mitigations.
- Review monitoring for WSA traffic-processing stoppages or repeated proxy outages.
- Verify controls limiting authenticated access to proxy use.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
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CWE-20: Exact CWE lookup
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Open ATT&CK lookupCVE-2019-1884 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.7 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H3.14Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
7.7HighVector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20190703 Cisco Web Security Appliance Web Proxy Denial of Service VulnerabilityCVE reference · vendor-advisory, x_refsource_CISCO
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Input Validation
Improper Input Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.