How severe is CVE-2026-41855?

CVE-2026-41855 has a CVSS score of 8.1/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2026-41855?

Affected package information for CVE-2026-41855 is not yet fully mapped. Check the official advisory links for details.

How do I fix CVE-2026-41855?

No patched version of the affected component has shipped for CVE-2026-41855 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.

How do I detect CVE-2026-41855 in my code and dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2026-41855 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.

How does O3 Security protect against CVE-2026-41855?

O3 pinpoints whether CVE-2026-41855 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2026-41855 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-41855 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-2026-41855?

CVE-2026-41855 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 17th 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-2026-41855?

CVE-2026-41855 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-2026-41855 published, and has it been updated?

CVE-2026-41855 was published on June 9, 2026 and was last updated on June 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.

CVE-2026-41855: Deserialization of Untrusted Data (High 8.1)

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk17th percentile0.00%

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.

Description

In an untrusted JMS environment, org.springframework.jms.support.converter.MappingJackson2MessageConverter and org.springframework.jms.support.converter.JacksonJsonMessageConverter allow arbitrary class instantiation, which can lead to unauthorized actions via gadget class deserialization.

Affected versions: Spring Framework 7.0.0 through 7.0.7; 6.2.0 through 6.2.18; 6.1.0 through 6.1.27; 5.3.0 through 5.3.48.

Detection & mitigation playbook

Vulnerability

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Remediation status
No patched version of the affected component has shipped for CVE-2026-41855 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
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 pinpoints whether CVE-2026-41855 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2026-41855. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

In an untrusted JMS environment, org.springframework.jms.support.converter.MappingJackson2MessageConverter and org.springframework.jms.support.converter.JacksonJsonMessageConverter allow arbitrary class instantiation, which can lead to unauthorized actions via gadget class deserialization. Affected versions: Spring Framework 7.0.0 through 7.0.7; 6.2.0 through 6.2.18; 6.1.0 through 6.1.27; 5.3.0 through 5.3.48.

O3 Security · Impact-Aware SCA

Is CVE-2026-41855 in your dependencies?

O3 detects CVE-2026-41855 across dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works

CVE-2026-41855

EPSS Exploitation Probability

Description

Detection & mitigation playbook

Detect

Remediation status

Mitigate without a patch

How O3 protects you

Frequently Asked Questions

Is CVE-2026-41855 in your dependencies?