Cisco IOS XE Software Guest Shell Unauthorized File System Access Vulnerability

published 2020-09-24 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-24774

cvss: 6.0; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 20%
public exploits: 0; none known

A vulnerability in the file system permissions of Cisco IOS XE Software could allow an authenticated, local attacker to obtain read and write access to critical configuration or system files. The vulnerability is due to insufficient file system permissions on an affected device. An attacker could exploit this vulnerability by connecting to an affected device's guest shell, and accessing or modifying restricted files. A successful exploit could allow the attacker to view or modify restricted information or configurations that are normally not accessible to system administrators.

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 23 mo ago (2024-11-13)

Exploit prediction

0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	6.0	CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
NVD	3.1	6.0	CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
NVD	2.0	3.6	AV:L/AC:L/Au:N/C:P/I:P/A:N

Affected products

Cisco Cisco IOS XE Software

Classification

Weakness

CWE-284 Improper Access Control
CWE-732 Incorrect Permission Assignment for Critical Resource

Technology feeds

Cisco IOS rss critical rss

References

tools.cisco.com /security/center/content/CiscoSecurityAdvisory/cisco-sa-unauth-file-access-eBTWkKVW
vendor-advisory

Sources

CVE List CVE-2020-3503
NVD CVE-2020-3503

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.

Summary