How severe is CVE-2023-39343?

CVE-2023-39343 has a CVSS score of 4.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2023-39343?

CVE-2023-39343 affects the following packages: sulu/sulu (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2023-39343?

Update sulu/sulu to 2.5.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-39343 is resolved across your whole dependency graph.

How do I detect CVE-2023-39343 in my Packagist dependencies?

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

How do I mitigate CVE-2023-39343 if there is no patch (or I can't update yet)?

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.

Is CVE-2023-39343 actively exploited in the wild?

No public exploit code has been indexed for CVE-2023-39343 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-2023-39343?

CVE-2023-39343 has an EPSS (Exploit Prediction Scoring System) score of 0.6%, placing it in the 49th 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-2023-39343?

CVE-2023-39343 is classified as CWE-204 (CWE-204). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2023-39343 published, and has it been updated?

CVE-2023-39343 was published on August 4, 2023 and was last updated on October 28, 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-2023-39343 — sulu

MEDIUMFix: sulu/sulu@5f6c98b

CVE-2023-39343 is a medium-severity (CVSS 4.3) CWE-204 vulnerability in sulu/sulu. A fix is available for sulu/sulu — see the affected versions and patch details below.

Sulu Observable Response Discrepancy on Admin Login

Also known asGHSA-wmwf-49vv-p3mr

Published

Aug 4, 2023

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 24, 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-2023-39343.

EPSS Exploitation Probability

via FIRST.org ↗

0.6%probability of exploitation in next 30 days

Lower Risk+0.00%

Lower risk than most CVEs49th percentile — riskier than 49% 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

🐘sulu/sulu

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

Impact

It allows over the Admin Login form to detect which user (username, email) exists and which one do not exist.

Impacted by this issue are Sulu installation >= 2.5.0 and <2.5.10 using the newer Symfony Security System which is default since Symfony 6.0 but can be enabled in Symfony 5.4. Sulu Installation not using the old Symfony 5.4 security System and previous version are not impacted by this Security issue.

Patches

The problem has been patched in version 2.5.10.

Workarounds

Create a custom AuthenticationFailureHandler which does not return the $exception->getMessage(); instead the $exception->getMessageKey();

References

Currently no references.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`sulu/sulu`	≥ 2.5.0&&< 2.5.10	2.5.10`composer require sulu/sulu:^2.5.10`

Affected Products

1 product · 1 configurations

Application

sulusulu

≥ 2.5.0 && < 2.5.10

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for sulu/sulu, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update sulu/sulu to 2.5.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-39343 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.

Frequently Asked Questions

### Impact It allows over the Admin Login form to detect which user (username, email) exists and which one do not exist. Impacted by this issue are Sulu installation >= 2.5.0 and <2.5.10 using the newer Symfony Security System which is default since Symfony 6.0 but can be enabled in Symfony 5.4. Sulu Installation not using the old Symfony 5.4 security System and previous version are not impacted by this Security issue. ### Patches The problem has been patched in version 2.5.10. ### Workarounds Create a custom AuthenticationFailureHandler which does not return the `$exception->getMessage