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CVE-2021-29441

79
FAUCET Score

CVE-2021-29441 is a critical authentication bypass vulnerability affecting Alibaba Nacos versions prior to 1.4.1. This flaw allows unauthenticated attackers to bypass security checks by spoofing the user-agent HTTP header, enabling them to perform administrative tasks on the Nacos server. With a CVSS score of 9.8 (CRITICAL) and an EPSS score indicating high exploitability, the vulnerability poses a significant risk. While not on the KEV catalog or Hot List, public Nuclei templates exist for exploitation, though there is no evidence of active exploitation or widespread community discussion.

Impacted Technologies

VendorProductVersion(s)CPE
< 1.4.1CPE matchmatch criteria
cpe:2.3:a:alibaba:nacos:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

8.6HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
4.0
CvssVersion
3.1

Exploit Intelligence

EPSS Score
68.92%
Probability of exploitation in next 30 days
EPSS Percentile
99.3%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
Nuclei: CVE-2021-29441 · Apr 28, 2021
This CVE's current EPSS score of 0.6892 is in the 97th percentile among its peer group of 36,835 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

github_advisorypatch availablevia nvd_reference
View patch
mavenpatch availablevia ghsa
Product: com.alibaba.nacos:nacos-commonFixed in: 1.4.1

Vendor Advisories (1)

mavenGHSA-36hp-jr8h-556fhigh

Authentication Bypass

Apr 27, 2021

References

github.com / advisories/GHSA-36hp-jr8h-556f
ExploitThird Party Advisory
github.com / alibaba/nacos/issues/4701
ExploitThird Party Advisory
github.com / alibaba/nacos/pull/4703
PatchThird Party Advisory