Security readout for executives and security teams
Plain-English summary
This flaw lets a remote, unauthenticated attacker get certain HTTP traffic past a configured Snort file policy on affected Cisco products. The business risk is not system takeover by itself, but reduced gateway inspection that could let malicious files reach users or systems.
Executive priority
Treat as a moderate-priority control-bypass issue. Prioritize internet-edge or high-trust network sensors where HTTP file policy is a key malware prevention layer, but do not handle as emergency active exploitation based on this bundle alone.
Technical view
CVE-2021-1495 is a Snort HTTP detection engine file-policy bypass caused by incorrect handling of specific HTTP header parameters. The listed affected product is Cisco Firepower Threat Defense Software. CVSS 3.1 is 5.8, network exploitable, low complexity, no privileges or user interaction required, with limited integrity impact.
Likely exposure
Exposure is most relevant where Cisco Firepower Threat Defense uses Snort HTTP inspection and configured file policies to block or control HTTP-delivered files. Debian Snort security advisories are also cited, but the bundle does not provide exact affected versions.
Exploitation context
The bundle says exploitation requires crafted HTTP packets passing through an affected device. CISA KEV is false, and no provided source states active exploitation. Public evidence here supports a bypass risk, not confirmed in-the-wild exploitation.
Researcher notes
Key limits: the bundle does not include exact affected or fixed version ranges, workarounds, CWE mapping, or exploit telemetry. Analysis should stay tied to the Cisco advisory and Debian security notices before making environment-specific exposure or remediation claims.
Mitigation direction
- Review the Cisco advisory for affected releases, fixed releases, and workarounds.
- Apply vendor-provided Cisco or Snort security updates after normal change testing.
- For Debian-managed Snort, follow DLA-3317-1 and DSA-5354 guidance.
- Use compensating malware controls for HTTP downloads until affected sensors are updated.
- Confirm critical HTTP file policies remain enabled and correctly scoped.
Validation and detection
- Inventory Cisco Firepower Threat Defense deployments using Snort HTTP file policies.
- Compare installed versions against the Cisco advisory and Debian advisories where relevant.
- Check whether HTTP file policy enforcement is relied on for high-risk segments.
- Review security logs for suspicious HTTP-delivered files around exposed paths.
- After updating, run vendor-safe regression tests for HTTP file policy enforcement.
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
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CVE-2021-1495 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
- Medium
- CVSS
- 5.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
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:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N3.91.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.8MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- 20210428 Multiple Cisco Products Snort HTTP Detection Engine File Policy Bypass VulnerabilityCVE reference · vendor-advisory
- [debian-lts-announce] 20230210 [SECURITY] [DLA 3317-1] snort security updateCVE reference · mailing-list
- DSA-5354CVE reference · vendor-advisory
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.