CVE-2021-21252 [Medium] | Denial of Service in Jquery Validation

The jQuery Validation Plugin provides drop-in validation for your existing forms. It is published as an npm package "jquery-validation". jquery-validation before version 1.19.3 contains one or more regular expressions that are vulnerable to ReDoS (Regular Expression Denial of Service). This is fixed in 1.19.3.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.70%	3.53%	+2.83%
2	2026-03-15	0.50%	0.70%	+0.20%
3	2026-03-04	—	0.50%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.70%

3.53%

+2.83%

2026-03-15

0.50%

0.70%

+0.20%

2026-03-04

—

0.50%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
5.3	3.1	MEDIUM	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L` 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:L) Might cause slowdowns, glitches, or partial disruption—not a full brick.	3.9	1.4	[email protected]
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]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

5.3

3.1

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L 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:L): Might cause slowdowns, glitches, or partial disruption—not a full brick.

3.9

1.4

[email protected]

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]

OS Trackers for CVE-2021-21252

vendor	priority	summary	link
`debian`	unimportant	CVE-2021-21252 unimportant priority: Debian including 4 source packages (civicrm, node-jquery-validation, otrs2, phpmyadmin), 8 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 7, open 1.	https://security-tracker.debian.org/tracker/CVE-2021-21252
`redhat`	medium	—	https://access.redhat.com/security/cve/CVE-2021-21252
`ubuntu`	medium	CVE-2021-21252 medium priority: Ubuntu including 3 source packages (civicrm, otrs2, phpmyadmin), 48 status rows across 16 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 15, needed 12, not-affected 10, ignored 8, needs-triage 2, released 1.	https://ubuntu.com/security/CVE-2021-21252

Affected software / configurations for CVE-2021-21252

Vendor	Product	Version	Raw CPE
jqueryvalidation	jquery_validation	< 1.19.3	cpe:2.3:a:jqueryvalidation:jquery_validation::::::node.js::*
netapp	snapcenter	—	cpe:2.3:a:netapp:snapcenter:-:::::::*

References for CVE-2021-21252

URL	Tags
https://github.com/jquery-validation/jquery-validation/commit/5d8f29eef363d043a8fec4eb86d42cadb5fa5f7d	Patch Third Party Advisory
https://github.com/jquery-validation/jquery-validation/pull/2371	Patch Third Party Advisory
https://github.com/jquery-validation/jquery-validation/security/advisories/GHSA-jxwx-85vp-gvwm	Third Party Advisory
https://lists.debian.org/debian-lts-announce/2023/08/msg00040.html
https://security.netapp.com/advisory/ntap-20210219-0005/	Third Party Advisory
https://www.npmjs.com/package/jquery-validation	Product Third Party Advisory

URL

CVE-2021-21252 | Regular expression denial of service in jquery-validation

Exploit prediction scoring system (EPSS) score for CVE-2021-21252

Common vulnerability scoring system (CVSS) metrics for CVE-2021-21252

Weakness enumeration for CVE-2021-21252

GitHub Security Advisory for CVE-2021-21252

OS Trackers for CVE-2021-21252

Affected software / configurations for CVE-2021-21252

References for CVE-2021-21252