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-2021-34705

20
FAUCET Score

CVE-2021-34705 is a medium-severity vulnerability affecting Cisco IOS and IOS XE Software's Voice Telephony Service Provider (VTSP) service. It allows an unauthenticated, remote attacker to bypass configured dial patterns on Foreign Exchange Office (FXO) interfaces by sending a malformed dial string via ISDN or SIP. This could lead to toll fraud and unexpected financial costs for affected organizations. There is no evidence of active exploitation, publicly available exploit code, or significant community discussion surrounding this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
12.3\(7\)xmCPE matchmatch criteria
cpe:2.3:o:cisco:ios:12.3\(7\)xm:*:*:*:*:*:*:*
12.3\(7\)xrCPE matchmatch criteria
cpe:2.3:o:cisco:ios:12.3\(7\)xr:*:*:*:*:*:*:*
12.3\(7\)xr1CPE matchmatch criteria
cpe:2.3:o:cisco:ios:12.3\(7\)xr1:*:*:*:*:*:*:*
12.3\(7\)xr2CPE matchmatch criteria
cpe:2.3:o:cisco:ios:12.3\(7\)xr2:*:*:*:*:*:*:*
12.3\(7\)xr3CPE matchmatch criteria
cpe:2.3:o:cisco:ios:12.3\(7\)xr3:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

5.3MEDIUM

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
LOW
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
1.4
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.01%
Probability of exploitation in next 30 days
EPSS Percentile
59.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.0101 is in the 37th percentile among its peer group of 23,701 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

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

Remediation

Vendor Patches (1)

ciscovendor investigatingvia nvd_reference
View patch

References

tools.cisco.com / security/center/content/CiscoSecurityAdvisory/cisco-sa-fxo-pattern-bypass-jUXgygYv
Vendor Advisory