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Fencer Vulns
high 8.6

CVE-2019-1740 json

Cisco IOS and IOS XE Software Network-Based Application Recognition Denial of Service Vulnerabilities

published 2019-03-27 7 y ago modified 2026-06-17 4 mo ago also EUVD-2019-10297

cvss
8.6
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.2%
EPSS 2.2% chance of exploitation in 30 days, percentile 82%
public exploits
0
none known

Summary

A vulnerability in the Network-Based Application Recognition (NBAR) feature of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload. This vulnerability are due to a parsing issue on DNS packets. An attacker could exploit this vulnerability by sending crafted DNS packets through routers that are running an affected version and have NBAR enabled. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition.

Patch / fix

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
23 mo ago

Exploit prediction

2.19% chance of exploitation in the next 30 days, higher than 82% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.0 8.6 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
NVD 3.1 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
NVD 2.0 7.8 AV:N/AC:L/Au:N/C:N/I:N/A:C

Affected products

  • Cisco Cisco IOS and Cisco IOS-XE Software

Classification

Weakness
  • CWE-20 Improper Input Validation
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.