How severe is CVE-2021-25281?

CVE-2021-25281 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-25281?

CVE-2021-25281 affects the following packages: salt (PyPI), salt (PyPI), salt (PyPI), salt (PyPI), salt (PyPI), salt (PyPI), salt (PyPI), salt (PyPI), and 1 more. Ecosystems affected: PyPI.

How do I fix CVE-2021-25281?

Update salt to 2015.8.13 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-25281 is resolved across your whole dependency graph.

How do I detect CVE-2021-25281 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for salt, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-25281 if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is CVE-2021-25281 actively exploited in the wild?

Yes. There are 5 known exploit references for CVE-2021-25281, including 4 in-the-wild exploitations observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2021-25281?

CVE-2021-25281 has an EPSS (Exploit Prediction Scoring System) score of 73.1%, placing it in the 99th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

What type of vulnerability is CVE-2021-25281?

CVE-2021-25281 is classified as Improper Authentication (CWE-287). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Is there exploit tooling available for CVE-2021-25281?

A Nuclei detection template exists for CVE-2021-25281, meaning automated scanners can fingerprint it. A Metasploit module references CVE-2021-25281, which lowers the barrier to weaponization. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2021-25281 published, and has it been updated?

CVE-2021-25281 was published on February 27, 2021 and was last updated on October 20, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍

🐍 PyPI

Not in CISA KEV

CRITICAL severity

CVE-2021-25281 — salt

CRITICAL

CVE-2021-25281 is a critical-severity (CVSS 9.8) Improper Authentication vulnerability in salt. 5 public exploit or proof-of-concept references are indexed, so weaponization risk is real. A fix is available for salt — see the affected versions and patch details below.

SaltStack Salt Improper Authentication vulnerability

Also known asGHSA-xxw3-765m-f37pPYSEC-2021-50

Published

Feb 27, 2021

Updated

Oct 20, 2026

Affected

9 pkgs

Patched

8 / 9

Exploits

5 known

Exploitation data as of Nov 5, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2021-25281.

EPSS Exploitation Probability

via FIRST.org ↗

73.1%probability of exploitation in next 30 days

Very High Risk0.00%

Lower risk than most CVEs99th percentile — riskier than 99% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

9 pkgs affected

🐍salt🐍salt🐍salt🐍salt🐍salt🐍salt🐍salt🐍salt+1 more

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

An issue was discovered in through SaltStack Salt before 3002.5. salt-api does not honor eauth credentials for the wheel_async client. Thus, an attacker can remotely run any wheel modules on the master.

Affected Packages

9 total 8 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`salt`	all versions	2015.8.13`pip install --upgrade 'salt==2015.8.13'`
🐍PyPI	`salt`	≥ 2016.3.0&&< 2016.11.5	2016.11.5`pip install --upgrade 'salt==2016.11.5'`
🐍PyPI	`salt`	≥ 2016.11.7&&< 2016.11.10	2016.11.10`pip install --upgrade 'salt==2016.11.10'`
🐍PyPI	`salt`	≥ 2017.5.0&&< 2017.7.8	2017.7.8`pip install --upgrade 'salt==2017.7.8'`
🐍PyPI	`salt`	≥ 2018.2.0	No fix
🐍PyPI	`salt`	≥ 2019.2.0&&< 2019.2.8	2019.2.8`pip install --upgrade 'salt==2019.2.8'`

Affected Products

3 products · 21 configurations

debian linuxdebian

3 versions

9.010.011.0

fedorafedoraproject

3 versions

323334

Application

saltsaltstack

≥ 3002 && ≤ 2018.3.5

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

An issue was discovered in through SaltStack Salt before 3002.5. salt-ap…

github.comMetasploitMar 2021

Report on github.com

github.comGithubFeb 2021

Report on github.com

github.comGithubApr 2021

Report on packetstormsecurity.com

packetstormsecurity.comNVDNov 2021

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for salt, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update salt to 2015.8.13 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-25281 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

How to detect CVE-2021-25281

A community-maintained Nuclei template exists for this CVE. You can scan for it directly:

nuclei -id cve-2021-25281 -u https://target

Template: SaltStack Salt <3002.5 - Auth Bypass
Severity: critical
Impact: Unauthenticated attackers can remotely execute any wheel modules on the Salt master by bypassing eauth credentials, leading to complete infrastructure compromise and control over all managed systems.
Remediation: Upgrade to SaltStack Salt version 3002.5 or later to mitigate this vulnerability.

Template by ProjectDiscovery nuclei-templates (madrobot), MIT licensed. View the full template. Scan only systems you are authorised to test.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2021-25281 in your dependencies?

Find it across PyPI, including transitive dependencies.

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