How severe is CVE-2026-87830?

CVE-2026-87830 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2026-87830 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-87830?

CVE-2026-87830 affects Apache Wss4j. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-87830?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2026-87830 published?

CVE-2026-87830 was published on 2026-09-30 and last updated on 2026-10-06.

CVE-2026-87830

CVE-2026-87830 is a critical-severity vulnerability in Apache Wss4j with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-917.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
EPSS exploit prediction: 0% (7th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-917
Affected product: Apache Wss4j
Published: 2026-09-30
Last modified: 2026-10-06

Description

In the StAX streaming WS-SecurityPolicy validator, certain relative or unsupported XPath expressions can be converted into paths that never match the actual XML element path. A remote SOAP peer may therefore send a required element without the expected signature or encryption. Users are recommended to upgrade to versions 4.0.2 or 3.0.6 or 2.4.4, which fix this issue.

Frequently asked questions

What is CVE-2026-87830?: In the StAX streaming WS-SecurityPolicy validator, certain relative or unsupported XPath expressions can be converted into paths that never match the actual XML element path. A remote SOAP peer may therefore send a required element without the expected signature or encryption. Users are recommended to upgrade to versions 4.0.2 or 3.0.6 or 2.4.4, which fix this issue.
How severe is CVE-2026-87830?: CVE-2026-87830 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2026-87830 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-87830?: CVE-2026-87830 affects Apache Wss4j. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-87830?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-87830 published?: CVE-2026-87830 was published on 2026-09-30 and last updated on 2026-10-06.

References

Affected products (1)

cpe:2.3:a:apache:wss4j:*:*:*:*:*:*:*:*

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