How severe is CVE-2023-27531?

CVE-2023-27531 has a CVSS score of 5.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2023-27531?

CVE-2023-27531 affects the following packages: kredis (RubyGems). Ecosystems affected: RubyGems.

How do I fix CVE-2023-27531?

Update kredis to 1.3.0.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-27531 is resolved across your whole dependency graph.

How do I detect CVE-2023-27531 in my RubyGems dependencies?

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

How do I mitigate CVE-2023-27531 if there is no patch (or I can't update yet)?

Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.

Is CVE-2023-27531 actively exploited in the wild?

No public exploit code has been indexed for CVE-2023-27531 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-2023-27531?

CVE-2023-27531 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 46th 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-2023-27531?

CVE-2023-27531 is classified as Deserialization of Untrusted Data (CWE-502). 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-2023-27531 published, and has it been updated?

CVE-2023-27531 was published on June 9, 2023 and was last updated on January 10, 2025. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

💎

💎 RubyGems

Not in CISA KEV

MEDIUM severity

CVE-2023-27531 — kredis

MEDIUMFix: rails/kredis@d576b7a

CVE-2023-27531 is a medium-severity (CVSS 5.3) Deserialization of Untrusted Data vulnerability in kredis. A fix is available for kredis — see the affected versions and patch details below.

Kredis JSON Possible Deserialization of Untrusted Data Vulnerability

Published

Jun 9, 2023

Updated

Jan 10, 2025

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 2, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

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-2023-27531.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs46th percentile — riskier than 46% 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

1 pkg affected

💎kredis

Real-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

There is a deserialization of untrusted data vulnerability in the Kredis JSON deserialization code. This vulnerability has been assigned the CVE identifier CVE-2023-27531.

'Not affected: None.' 'Versions Affected: All.' 'Fixed Versions: 1.3.0.1'

Impact Carefully crafted JSON data processed by Kredis may result in deserialization of untrusted data, potentially leading to deserialization of unexpected objects in the system.

Any applications using Kredis with JSON are affected.

Releases The fixed releases are available at the normal locations.

Workarounds There are no feasible workarounds for this issue.

Patches To aid users who aren’t able to upgrade immediately we have provided patches for the two supported release series. They are in git-am format and consist of a single changeset.

1-3-0-1-kredis.patch - Patch for 1.3.0 series

Credits Thank you ooooooo_k 7 for reporting this!

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
💎RubyGems	`kredis`	all versions	1.3.0.1`bundle update kredis --conservative`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for kredis, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update kredis to 1.3.0.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-27531 is resolved across your whole dependency graph.
Workarounds
Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.

Frequently Asked Questions

There is a deserialization of untrusted data vulnerability in the Kredis JSON deserialization code. This vulnerability has been assigned the CVE identifier CVE-2023-27531. 'Not affected: None.' 'Versions Affected: All.' 'Fixed Versions: 1.3.0.1' Impact Carefully crafted JSON data processed by Kredis may result in deserialization of untrusted data, potentially leading to deserialization of unexpected objects in the system. Any applications using Kredis with JSON are affected. Releases The fixed releases are available at the normal locations. Workarounds There are no feasible wo