How severe is CVE-2021-27938?

CVE-2021-27938 has a CVSS score of 6.1/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2021-27938?

CVE-2021-27938 affects the following packages: symbiote/silverstripe-queuedjobs (Packagist), symbiote/silverstripe-queuedjobs (Packagist), symbiote/silverstripe-queuedjobs (Packagist), symbiote/silverstripe-queuedjobs (Packagist), symbiote/silverstripe-queuedjobs (Packagist), symbiote/silverstripe-queuedjobs (Packagist), symbiote/silverstripe-queuedjobs (Packagist), symbiote/silverstripe-queuedjobs (Packagist), and 1 more. Ecosystems affected: Packagist.

How do I fix CVE-2021-27938?

Update symbiote/silverstripe-queuedjobs to 3.0.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-27938 is resolved across your whole dependency graph.

How do I detect CVE-2021-27938 in my Packagist dependencies?

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

How do I mitigate CVE-2021-27938 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2021-27938 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-27938 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-27938?

CVE-2021-27938 has an EPSS (Exploit Prediction Scoring System) score of 0.8%, placing it in the 54th 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. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-27938?

CVE-2021-27938 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2021-27938 published, and has it been updated?

CVE-2021-27938 was published on March 16, 2021 and was last updated on August 27, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘

🐘 Packagist

Not in CISA KEV

MEDIUM severity

CVE-2021-27938 — silverstripe-queuedjobs

MEDIUM

CVE-2021-27938 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in symbiote/silverstripe-queuedjobs. A fix is available for symbiote/silverstripe-queuedjobs — see the affected versions and patch details below.

XSS in CreateQueuedJobTask

Also known asGHSA-xgpf-p52j-pf7m

Published

Mar 16, 2021

Updated

Aug 27, 2026

Affected

9 pkgs

Patched

9 / 9

Exploits

None indexed

Exploitation data as of Oct 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.8%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs54th percentile — riskier than 54% of all scored CVEsHighest risk

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

How urgent is this, really

CVE-2021-27938 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

9 pkgs affected

🐘symbiote/silverstripe-queuedjobs🐘symbiote/silverstripe-queuedjobs🐘symbiote/silverstripe-queuedjobs🐘symbiote/silverstripe-queuedjobs🐘symbiote/silverstripe-queuedjobs🐘symbiote/silverstripe-queuedjobs🐘symbiote/silverstripe-queuedjobs🐘symbiote/silverstripe-queuedjobs+1 more

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

Description

A vulnerability has been identified in the Silverstripe CMS 3 and 4 version of the symbiote/silverstripe-queuedjobs module. A Cross Site Scripting vulnerability allows an attacker to inject an arbitrary payload in the CreateQueuedJobTask dev task via a specially crafted URL.

Affected Packages

9 total 9 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`symbiote/silverstripe-queuedjobs`	≥ 3.0.0&&< 3.0.2	3.0.2`composer require symbiote/silverstripe-queuedjobs:^3.0.2`
🐘Packagist	`symbiote/silverstripe-queuedjobs`	≥ 3.1.0&&< 3.1.4	3.1.4`composer require symbiote/silverstripe-queuedjobs:^3.1.4`
🐘Packagist	`symbiote/silverstripe-queuedjobs`	≥ 4.0.0&&< 4.0.7	4.0.7`composer require symbiote/silverstripe-queuedjobs:^4.0.7`
🐘Packagist	`symbiote/silverstripe-queuedjobs`	≥ 4.1.0&&< 4.1.2	4.1.2`composer require symbiote/silverstripe-queuedjobs:^4.1.2`
🐘Packagist	`symbiote/silverstripe-queuedjobs`	≥ 4.2.0&&< 4.2.4	4.2.4`composer require symbiote/silverstripe-queuedjobs:^4.2.4`
🐘Packagist	`symbiote/silverstripe-queuedjobs`	≥ 4.3.0&&< 4.3.3	4.3.3`composer require symbiote/silverstripe-queuedjobs:^4.3.3`

Affected Products

1 product · 9 configurations

Application

silverstripe queued jobssymbiote

≥ 4.6.0 && < 4.6.4

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for symbiote/silverstripe-queuedjobs, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update symbiote/silverstripe-queuedjobs to 3.0.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-27938 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2021-27938 in your dependencies?

Find it across Packagist, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

6.1/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Raw vector

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

CWE Classification

CWE-79Cross-site Scripting (XSS)

Weaponization

No known public exploit tooling found.

OpenSSF Scorecard

Package health score

security-advisories

4.8/10

Code-Review10/10

Maintained10/10

Branch-Protection0/10

Assessed Oct 5, 2026

Timeline

Disclosed

Mar 16, 2021

Last updated

Aug 27, 2026

Identifiers

CVE-2021-27938

GHSA-xgpf-p52j-pf7m

References

Advisorygithub.com Advisorysilverstripe.org Advisorynvd.nist.gov Webgithub.com

Related vulnerabilities

This CVE is medium severity; 8 of 8 other CVEs with CWE-79 are rated as high or higher (top: high).

CVE-2026-91127CVE-2026-77606CVE-2026-84992CVE-2026-77608CVE-2026-77607GHSA-9rcc-pmj8-ffhrCVE-2026-77616CVE-2025-61682Browse all CWE-79

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedAug 27, 2026