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CVE-2021-3374

35
FAUCET Score

CVE-2021-3374 is a directory traversal vulnerability in RStudio Shiny Server versions prior to 1.5.16, allowing unauthenticated attackers to read application source code by exploiting an encoded slash. With a CVSS score of 5.3 (Medium), this vulnerability has a low attack complexity and no user interaction required, leading to a potential impact of information disclosure. While not listed in CISA's KEV catalog, Nuclei templates exist for this Local File Inclusion flaw, indicating readily available exploit code, yet there is no evidence of active exploitation or significant community discussion.

Impacted Technologies

VendorProductVersion(s)CPE
< 1.5.16CPE matchmatch criteria
cpe:2.3:a:rstudio:shiny_server:*:*:*:*:pro:*:*:*

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:L/I:N/A:N

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

Exploit Intelligence

EPSS Score
14.42%
Probability of exploitation in next 30 days
EPSS Percentile
96.2%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
Nuclei: CVE-2021-3374 · Apr 14, 2021
This CVE's current EPSS score of 0.1442 is in the 96th percentile among its peer group of 23,703 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

Remediation records are not available for this CVE.

References

blog.rstudio.com / 2021/01/13/shiny-server-1-5-16-update
Vendor Advisory
github.com / colemanjp/shinyserver-directory-traversal-source-code-leak
ExploitThird Party Advisory