Cyber Resilience

CVE-2023-37467

XSS in Discourse 1.1.0 … 3.1.0

XSS
Published
28 July 2023
Modified
21 November 2024
Patch / advisory
View advisory
CVSS Score v3.1 6.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
EPSS Score 0.0037 29th percentile
Risk Priority 51 floored blend · peak EPSS

Summary

CVE-2023-37467 is a medium-severity Reusing a Nonce, Key Pair in Encryption (CWE-323) vulnerability in Discourse Discourse. Its CVSS base score is 6.8 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Browser Session Hijacking (T1185); ranked at the 29th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

A04:2025 Cryptographic FailuresA05:2025 Injection

EU & UK References

Vulnerability Data

Discourse is an open source discussion platform. Prior to version 3.1.0.beta7 of the `beta` and `tests-passed` branches, a CSP (Content Security Policy) nonce reuse vulnerability was discovered could allow cross-site scripting (XSS) attacks to bypass CSP protection for anonymous (i.e.…

more

unauthenticated) users. There are no known XSS vectors at the moment, but should one be discovered, this vulnerability would allow the XSS attack to bypass CSP and execute successfully. This vulnerability isn't applicable to logged-in users. Version 3.1.0.beta7 contains a patch. The stable branch doesn't have this vulnerability. A workaround to prevent the vulnerability is to disable Google Tag Manager, i.e., unset the `gtm container id` setting.

CWE(s)
CWE-323CWE-79

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.
attack.mitre.org →
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.
attack.mitre.org →
T1659 Content Injection Initial Access
Adversaries may gain access and continuously communicate with victims by injecting malicious content into systems through online network traffic.
attack.mitre.org →
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.
attack.mitre.org →
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.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-22454Same product: Discourse Discourse
CVE-2023-25172Same product: Discourse Discourse
CVE-2023-22455Same product: Discourse Discourse
CVE-2023-26040Same product: Discourse Discourse
CVE-2023-29196Same product: Discourse Discourse
CVE-2023-43659Same product: Discourse Discourse
CVE-2023-36473Same product: Discourse Discourse
CVE-2023-30538Same product: Discourse Discourse
CVE-2023-22468Same product: Discourse Discourse
CVE-2023-47119Same product: Discourse Discourse

Affected Assets

discourse
discourse
1.1.0, 1.2.0, 1.3.0, 1.4.0, 1.5.0

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)
  • V6.8.3
  • V11.3.4
  • V1.1.2
  • V1.3.2

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

CA-8 Penetration Testing
addresses: CWE-79

Penetration testing submits XSS payloads to web applications, detecting cross-site scripting flaws for subsequent remediation.

SI-10 Information Input Validation
addresses: CWE-79

Validates web inputs to reject script-related content that could produce XSS.

SI-15 Information Output Filtering
addresses: CWE-79

Output validation against expected content can reject or sanitize script content in generated web pages, reducing XSS exploitability.

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 prevent nonce/key reuse errors in cryptographic implementations.

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.

A.8.24 Use of cryptography mostly match
prevents

Mandates proper cryptographic key and nonce management, directly preventing nonce/key-pair reuse.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing can detect nonce reuse, yet the control addresses many other issues beyond this CWE.

A.5.6 Contact with special interest groups partial match
prevents

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

A.5.7 Threat intelligence partial match
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.

A.8.25 Secure development life cycle partial match
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.

A.8.28 Secure coding partial match
prevents

Secure-coding rules can require unique nonces, but the control is broader than this single weakness.

References