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-2018-8899

20
FAUCET Score

CVE-2018-8899 describes a cross-site scripting (XSS) vulnerability in IdentityServer4 versions 1.x before 1.5.3 and 2.x before 2.1.3, where the redirect URI on the authorization response page is not properly encoded. This medium-severity vulnerability (CVSS 6.1) can be exploited with low complexity via a network attack requiring user interaction, potentially leading to limited confidentiality and integrity impacts. There is no evidence of active exploitation, publicly available exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
>= 1.0.0, <= 1.5.2CPE matchmatch criteria
cpe:2.3:a:identityserver:identityserver4:*:*:*:*:*:*:*:*
>= 2.0.0, <= 2.1.2CPE matchmatch criteria
cpe:2.3:a:identityserver:identityserver4:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

6.1MEDIUM

CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality Impact
LOW
Integrity Impact
LOW
Availability Impact
NONE
Exploitability Score
2.8
Impact Score
2.7
CvssVersion
3.0

Exploit Intelligence

EPSS Score
1.26%
Probability of exploitation in next 30 days
EPSS Percentile
66.5%
Percentile rank of EPSS score among Peer Group
As of 2026-07-25
Model: v2026.06.15
This CVE's current EPSS score of 0.0126 is in the 79th percentile among its peer group of 26,209 CVEs.

Social Chatter

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

Media Mentions

No media coverage found for this CVE.

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

Remediation

Patch Available

Vendor Patches (1)

github_advisorypatch availablevia nvd_reference
View patch

References

github.com / IdentityServer/IdentityServer4/commit/21d0da227f50ac102de469a13bc5a15d2cc0f895
PatchThird Party Advisory
github.com / IdentityServer/IdentityServer4/issues/2164
Issue TrackingThird Party Advisory
github.com / IdentityServer/IdentityServer4/releases/tag/1.5.3
Third Party Advisory
github.com / IdentityServer/IdentityServer4/releases/tag/2.1.3
Third Party Advisory