Cyber Resilience

CVE-2024-21678

XSS in Atlassian Confluence Data Center ≤ 7.19.19

Published
20 February 2024
Modified
17 June 2026
Patch / advisory
CVSS Score v3.1 8.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N
EPSS Score 0.0047 39th percentile
Risk Priority 62 floored blend · peak EPSS

Summary

CVE-2024-21678 is a high-severity Cross-site Scripting (CWE-79) vulnerability in Atlassian Confluence Data Center. Its CVSS base score is 8.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Browser Session Hijacking (T1185); ranked at the 39th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

This High severity Stored XSS vulnerability was introduced in version 2.7.0 of Confluence Data Center. This Stored XSS vulnerability, with a CVSS Score of 8.5, allows an authenticated attacker to execute arbitrary HTML or JavaScript code on a victims browser…

more

which has high impact to confidentiality, low impact to integrity, no impact to availability, and requires no user interaction. Data Center Atlassian recommends that Confluence Data Center customers upgrade to the latest version. If you are unable to do so, upgrade your instance to one of the specified supported fixed versions: ||Affected versions||Fixed versions|| |from 8.7.0 to 8.7.1|8.8.0 recommended or 8.7.2| |from 8.6.0 to 8.6.1|8.8.0 recommended| |from 8.5.0 to 8.5.4 LTS|8.8.0 recommended or 8.5.5 LTS or 8.5.6 LTS| |from 8.4.0 to 8.4.5|8.8.0 recommended or 8.5.6 LTS| |from 8.3.0 to 8.3.4|8.8.0 recommended or 8.5.6 LTS| |from 8.2.0 to 8.2.3|8.8.0 recommended or 8.5.6 LTS| |from 8.1.0 to 8.1.4|8.8.0 recommended or 8.5.6 LTS| |from 8.0.0 to 8.0.4|8.8.0 recommended or 8.5.6 LTS| |from 7.20.0 to 7.20.3|8.8.0 recommended or 8.5.6 LTS| |from 7.19.0 to 7.19.17 LTS|8.8.0 recommended or 8.5.6 LTS or 7.19.18 LTS or 7.19.19 LTS| |from 7.18.0 to 7.18.3|8.8.0 recommended or 8.5.6 LTS or 7.19.19 LTS| |from 7.17.0 to 7.17.5|8.8.0 recommended or 8.5.6 LTS or 7.19.19 LTS| |Any earlier versions|8.8.0 recommended or 8.5.6 LTS or 7.19.19 LTS| Server Atlassian recommends that Confluence Server customers upgrade to the latest 8.5.x LTS version. If you are unable to do so, upgrade your instance to one of the specified supported fixed versions: ||Affected versions||Fixed versions|| |from 8.5.0 to 8.5.4 LTS|8.5.5 LTS or 8.5.6 LTS recommended | |from 8.4.0 to 8.4.5|8.5.6 LTS recommended| |from 8.3.0 to 8.3.4|8.5.6 LTS recommended| |from 8.2.0 to 8.2.3|8.5.6 LTS recommended| |from 8.1.0 to 8.1.4|8.5.6 LTS recommended| |from 8.0.0 to 8.0.4|8.5.6 LTS recommended| |from 7.20.0 to 7.20.3|8.5.6 LTS recommended| |from 7.19.0 to 7.19.17 LTS|8.5.6 LTS recommended or 7.19.18 LTS or 7.19.19 LTS| |from 7.18.0 to 7.18.3|8.5.6 LTS recommended or 7.19.19 LTS| |from 7.17.0 to 7.17.5|8.5.6 LTS recommended or 7.19.19 LTS| |Any earlier versions|8.5.6 LTS recommended or 7.19.19 LTS| See the release notes ([https://confluence.atlassian.com/doc/confluence-release-notes-327.html]). You can download the latest version of Confluence Data Center from the download center ([https://www.atlassian.com/software/confluence/download-archives]). This vulnerability was reported via our Bug Bounty program.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1185 Browser Session Hijacking Collection
Adversaries may take advantage of security vulnerabilities and inherent functionality in browser software to change content, modify user-behaviors, and intercept information as part of various browser session hijacking techniques.
T1539 Steal Web Session Cookie Credential Access
An adversary may steal web application or service session cookies and use them to gain access to web applications or Internet services as an authenticated user without needing credentials.
T1659 Content Injection Initial Access
Adversaries may gain access and continuously communicate with victims by injecting malicious content into systems through online network traffic.
T1189 Drive-by Compromise Initial Access
Adversaries may gain access to a system through a user visiting a website over the normal course of browsing.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-25837Shared CWE-79
CVE-2023-22438Shared CWE-79
CVE-2023-27614Shared CWE-79
CVE-2023-47164Shared CWE-79
CVE-2023-49145Shared CWE-79
CVE-2023-47853Shared CWE-79
CVE-2023-28474Shared CWE-79
CVE-2023-37636Shared CWE-79
CVE-2023-1006Shared CWE-79
CVE-2023-5005Shared CWE-79

Affected Assets

atlassian
confluence data center
≤ 7.19.19 · 7.20.0 — 8.5.5 · 8.6.0 — 8.7.2
atlassian
confluence server
≤ 7.19.19 · 7.20.0 — 8.5.5

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V1.1.2
  • V1.3.2

Mitigating Controls (NIST 800-53 r5) AI

Developer testing and evaluation can discover missing or incorrect input neutralization through targeted web-application tests.

Input validation directly enforces neutralization of untrusted data before it reaches web output generation.

Output filtering can catch or sanitize unneutralized script content before it is served to users.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly target introduction of XSS via coding standards/testing (mostly), yet the single broad outcome leaves many specific neutralization vectors unaddressed (partial).

PR.PS-02 partial match
prevents

Patching and EOL replacement can remediate known XSS instances in libraries or frameworks (partial) but do nothing to enforce input neutralization in application code (none).

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Secure-coding testing and automated code-analysis tools are applied to detect improper neutralization of script-related content during web-page generation.

prevents

Knowledge exchange on emerging attack techniques and patches reduces the likelihood that cross-site scripting flaws remain unaddressed in deployed applications.

prevents

Operational indicators of compromise for web-application attacks can be incorporated into WAF or input-filtering rules, lowering the likelihood that unsanitized data reaches the browser.

prevents

Requiring language-specific secure-coding standards and automated scanning during the SDLC catches missing output encoding or improper neutralization of untrusted data before the software reaches production.

prevents

Secure-coding standards, SAST scans and removal of insecure code samples together eliminate the failure to neutralize script content that produces cross-site scripting flaws.

none

Webpage malware scanning and block-listing of known malicious sites reduce the likelihood that reflected or stored script payloads reach a user’s browser.

References