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CVE-2023-26158

22
FAUCET Score

CVE-2023-26158 describes a Prototype Pollution vulnerability in all versions of the 'mockjs' package, specifically within the Util.extend function. This flaw allows an attacker to inject or modify properties of the JavaScript object prototype, potentially leading to denial of service or unexpected application behavior. With a CVSS score of 8.2 (HIGH), this vulnerability is easily exploitable over the network without user interaction, enabling an attacker to achieve high impact on availability and low impact on integrity. There is currently no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
<= 1.1.0CPE matchmatch criteria
cpe:2.3:a:mockjs:mock.js:*:*:*:*:*:node.js:*:*

CVSS Data

CVSS version used by this source: 3.1

8.2HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
LOW
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
4.2
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.80%
Probability of exploitation in next 30 days
EPSS Percentile
52.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0080 is in the 28th percentile among its peer group of 51,551 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Vendor Advisories (1)

npmGHSA-mh8j-9jvh-gjf6high

mockjs vulnerable to Prototype Pollution via the Util.extend function

Dec 8, 2023

References

github.com / nuysoft/Mock/blob/00ce04b92eb464e664a4438430903f2de96efb47/dist/mock.js%23L721-L755
Broken Link
security.snyk.io / vuln/SNYK-JS-MOCKJS-6051365
ExploitMitigationThird Party Advisory