CVE-2021-27292

Exp

ua-parser-js >= 0.7.14, fixed in 0.7.24, uses a regular expression which is vulnerable to denial of service. If an attacker sends a malicious User-Agent header, ua-parser-js will get stuck processing it for an extended period of time.

Published: 2021-03-17 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]

NVD Status：Modified，CVE State: published

View at NVD, CVE.org, EUVD

Threat Intelligence & Risk Assessment for CVE-2021-27292

EPSS CVSS GHSA Exploit-DB Affected OS Tracker

Conclusion & alert: CVE-2021-27292 is rated High Exploit Risk (74.5/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.44%). Core evidence: 1 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +1.17% over the last day, indicating growing attacker interest. Mandatory action: Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2021-27292

EDB-ID	Source	Kind	Published	Link
—	nvd_ref	exploit_tag		Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-27292

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-03	0.27%	1.44%	+1.17%
2	2026-03-04	0.15%	0.27%	+0.12%
3	2026-03-01	—	0.15%	—

Full EPSS history (36 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-27292

CVSS metrics for this CVE.

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
7.5	3.1	HIGH	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:N) No account or special rights needed—anonymous or random user is enough. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:N) Doesn’t really leak secrets in a meaningful way. Integrity (I:N) Data isn’t meaningfully altered or forged. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	3.9	3.6	[email protected]
5.0	2.0	MEDIUM	`AV:N/AC:L/Au:N/C:N/I:N/A:P` Click to expand Access vector (AV:N) Can be exploited remotely over network reachability. Access complexity (AC:L) Exploitation conditions are straightforward and predictable. Authentication (AU:N) No authentication is required. Confidentiality impact (C:N) No confidentiality impact. Integrity impact (I:N) No integrity impact. Availability impact (A:P) Partial availability impact.	10.0	2.9	[email protected]

Weakness enumeration for CVE-2021-27292

GitHub Security Advisory for CVE-2021-27292

GHSA-78cj-fxph-m83p · Severity: high · Ecosystem: npm — Regular Expression Denial of Service (ReDoS) in ua-parser-js

OS Trackers for CVE-2021-27292

vendor	priority	summary	link
`debian`	not yet assigned	CVE-2021-27292 not yet assigned priority: Debian including 1 source packages (node-ua-parser-js), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5.	https://security-tracker.debian.org/tracker/CVE-2021-27292
`redhat`	medium	—	https://access.redhat.com/security/cve/CVE-2021-27292
`ubuntu`	medium	CVE-2021-27292 medium priority: Ubuntu including 1 source packages (node-ua-parser-js), 16 status rows across 16 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 6, ignored 4, needed 3, DNE 2, released 1.	https://ubuntu.com/security/CVE-2021-27292

Affected software / configurations for CVE-2021-27292

Vendor	Product	Version	Raw CPE
ua-parser-js_project	ua-parser-js	>= 0.7.14, < 0.7.24	cpe:2.3:a:ua-parser-js_project:ua-parser-js::::::node.js::*

References for CVE-2021-27292

URL	Tags
https://gist.github.com/b-c-ds/6941d80d6b4e694df4bc269493b7be76	Exploit Third Party Advisory
https://github.com/faisalman/ua-parser-js/commit/809439e20e273ce0d25c1d04e111dcf6011eb566	Patch Third Party Advisory
https://github.com/pygments/pygments/commit/2e7e8c4a7b318f4032493773732754e418279a14	Patch Third Party Advisory

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