Cyber Resilience

CVE-2021-3271

MediumPublic PoC

Published: 18 February 2021

Published
18 February 2021
Modified
21 November 2024
KEV Added
—
Patch
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CVSS Score v3.1 4.8 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
EPSS Score 0.0041 61.8th percentile
Risk Priority 10 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-3271 is a medium-severity Cross-site Scripting (CWE-79) vulnerability in Pressbooks Pressbooks. Its CVSS base score is 4.8 (Medium).

Operationally, ranked in the top 38.2% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

PressBooks 5.17.3 contains a cross-site scripting (XSS). Stored XSS can be submitted via the Book Info's Long Description Body, and all actions to open or preview the books page will result in the triggering the stored XSS.

CWE(s)
CWE-79

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

pressbooks
pressbooks
≤ 5.17.3

Mitigating Controls

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.

References