Predictive Vulnerability Intelligence.

Product

  • Product
  • Pricing
  • Documentation

Company

  • About
  • Partnerships
  • Blog
  • Support

Legal

  • Terms
  • Privacy
  • Data Licensing

© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2025-20127

27
FAUCET Score

CVE-2025-20127 describes a denial-of-service vulnerability in the TLS 1.3 implementation of Cisco Secure Firewall ASA Software and FTD Software on Firepower 3100 and 4200 Series devices. An authenticated, remote attacker can exploit a flaw in the TLS_CHACHA20_POLY1305_SHA256 cipher to consume resources, preventing new SSL/TLS or VPN connections until the device is reloaded. This vulnerability carries a CVSS score of 7.7 (High), indicating a high impact on availability with low attack complexity and no user interaction required. While there is no known public exploit code or active exploitation, the vulnerability has garnered community discussion and media coverage, suggesting awareness within the cybersecurity landscape.

Impacted Technologies

VendorProductVersion(s)CPE
7.4.0CPE matchmatch criteria
cpe:2.3:a:cisco:firepower_threat_defense:7.4.0:*:*:*:*:*:*:*
7.4.1CPE matchmatch criteria
cpe:2.3:a:cisco:firepower_threat_defense:7.4.1:*:*:*:*:*:*:*
7.4.1.1CPE matchmatch criteria
cpe:2.3:a:cisco:firepower_threat_defense:7.4.1.1:*:*:*:*:*:*:*
7.4.2CPE matchmatch criteria
cpe:2.3:a:cisco:firepower_threat_defense:7.4.2:*:*:*:*:*:*:*
7.4.2.1CPE matchmatch criteria
cpe:2.3:a:cisco:firepower_threat_defense:7.4.2.1:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.7HIGH

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.1
Impact Score
4.0
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.62%
Probability of exploitation in next 30 days
EPSS Percentile
46.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0062 is in the 37th percentile among its peer group of 17,844 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.3 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Vendor Patches (1)

ciscovendor investigatingvia nvd_reference
View patch

References

sec.cloudapps.cisco.com / security/center/content/CiscoSecurityAdvisory/cisco-sa-3100_4200_tlsdos-2yNSCd54
Vendor Advisory