CVE-2023-46951 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in sidekiq-unique-jobs. A fix is available for sidekiq-unique-jobs — see the affected versions and patch details below.
XSS sidekiq-unique-jobs UI server vulnerability
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-46951.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2023-46951 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
sidekiq-unique-jobs💎sidekiq-unique-jobsReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
Summary
Cross site scripting (XSS) potentially exposing cookies / sessions / localStorage, fixed by sidekiq-unique-jobs v8.0.7.
Specifically, this is a Reflected (Server-Side), Non-Self, Cross Site Scripting vulnerability, considered a P3 on the BugCrowd taxonomy with the following categorization: Cross-Site Scripting (XSS) > Reflected > Non-Self
It was initially thought there was a second vulnerability (RCE), but it was a false alarm. Injection is impossible with Redis:
String escaping and NoSQL injection The Redis protocol has no concept of string escaping, so injection is impossible under normal circumstances using a normal client library. The protocol uses prefixed-length strings and is completely binary safe.
Ref: https://redis.io/docs/management/security/
XSS Vulnerability
Specially crafted GET request parameters handled by any of the following endpoints of sidekiq-unique-jobs' "admin" web UI, allow a super-user attacker, or an unwitting, but authorized, victim, who has received a disguised / crafted link, to successfully execute malicious code, which could potentially steal cookies, session data, or local storage data from the app the sidekiq-unique-jobs web UI is mounted in.
/changelogs/locks/expiring_locks
This means if your sidekiq-unique-jobs web UI is mounted at /sidekiq, the vulnerable paths are:
/sidekiq/changelogs/sidekiq/locks/sidekiq/expiring_locks
XSS vulnerability is an instance of CAPEC-32: XSS Through HTTP Query Strings, which is related to CWE-80. In certain cases where it results in a server error with status 500, it could be considered a vector for uncontrolled resource consumption, given that errors can be much more resource intensive that normal requests, and thus CWE-400 & CWE-754 may also be relevant.
Details
Fix for the XSS vulnerability was released in sidekiq-unique-jobs v8.0.7.
This is an analogous attack vector to that which affected sidekiq gem from version v7.0.4 to v7.0.7, and was given identifiers GHSA-h3r8-h5qw-4r35 & CVE-2023-1892.
The vulnerability in sidekiq-unique-jobs' was not fixed by sidekiq v7.0.8, nor the more recent sidekiq v7.2.0 releases; they are similar but unrelated, distinct vulnerabilities in adjacent projects.
Note #1: The admin web UI for sidekiq-unique-jobs is not protected by any authorization constraint in the default configuration. Auth constraints must be configured by the programmer. It is recommended and expected that users will configure authorization constrains on the "admin" UI. This is not specifically related to the vulnerability but may make users who fail to constrain their "admin" UI even more vulnerable.
Note #2: Most users of the library will not have configured the UI on a sandboxed subdomain, making all their cookies, localStorage data and session secrets vulnerable to exposure. The purpose of a sandboxed subdomain is expressly to prevent leaking sensitive data through XSS attacks.
XSS Fix PR: https://github.com/mhenrixon/sidekiq-unique-jobs/pull/829
PoC
XSS
Use a string like:
%22%3E%3Cimg/src/onerror=alert(document.domain)%3E
as the value for one of the parameters that are handled without escaping. Reference: https://liveoverflow.com/do-not-use-alert-1-in-xss/
- Visit /sidekiq/changelogs - with a crafted query string like one of the following:
a. Screenshot:
b.
filteris XSS vulnerable:?filter=%22%3E%3Cimg/src/onerror=alert(document.domain)%3Ec.countis vulnerable to triggering an application error (status 500), potentially allowing resource exhaustion?count=%22%3E%3Cimg/src/onerror=alert(document.domain)%3E- Screenshot:
- Screenshot:
- Visit /sidekiq/locks - with a crafted query string like one of the following:
a. Screenshot:
b.
filteris XSS vulnerable:?filter=%22%3E%3Cimg/src/onerror=alert(document.domain)%3Ec.countis vulnerable to triggering an application error (status 500), potentially allowing resource exhaustion?count=%22%3E%3Cimg/src/onerror=alert(document.domain)%3E- Screenshot:
- Screenshot:
- Visit /sidekiq/expiring_locks - with a crafted query string like one of the following:
a. Screenshot:
b.
filteris XSS vulnerable:?filter=%22%3E%3Cimg/src/onerror=alert(document.domain)%3E
Impact
This is a vulnerability of critical severity, which impacts many thousands of sites, since sidekiq-unique-jobs is widely deployed across the industry, with multiple attack vectors.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | sidekiq-unique-jobs | ≥ 8.0.0&&< 8.0.7 | 8.0.7bundle update sidekiq-unique-jobs --conservative |
| 💎RubyGems | sidekiq-unique-jobs | ≥ 6.0.0.rc7&&< 7.1.33 | 7.1.33bundle update sidekiq-unique-jobs --conservative |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for sidekiq-unique-jobs, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update sidekiq-unique-jobs to 8.0.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-46951 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-46951 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-46951. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-46951 in your dependencies?
O3 Security finds CVE-2023-46951 across RubyGems dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.