How severe is CVE-2026-87743?

CVE-2026-87743 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2026-87743 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-87743?

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

When was CVE-2026-87743 published?

CVE-2026-87743 was published on 2026-09-18 and last updated on 2026-09-22.

CVE-2026-87743

CVE-2026-87743 is a high-severity vulnerability with a CVSS 3.x base score of 7.5. 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-551.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (42nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-551
Published: 2026-09-18
Last modified: 2026-09-22

Description

A flaw was found in Quarkus HTTP security. An unauthenticated attacker can exploit a discrepancy in how paths are normalized between the security matcher and HTTP request dispatchers. This allows the attacker to craft a URL that the security matcher considers public, but which is then routed to a protected endpoint, leading to an authorization bypass and potential unauthorized access to sensitive information.

Frequently asked questions

What is CVE-2026-87743?: A flaw was found in Quarkus HTTP security. An unauthenticated attacker can exploit a discrepancy in how paths are normalized between the security matcher and HTTP request dispatchers. This allows the attacker to craft a URL that the security matcher considers public, but which is then routed to a protected endpoint, leading to an authorization bypass and potential unauthorized access to sensitive information.
How severe is CVE-2026-87743?: CVE-2026-87743 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2026-87743 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (42nd percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-87743?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-87743 published?: CVE-2026-87743 was published on 2026-09-18 and last updated on 2026-09-22.

References

Other CWE-551 vulnerabilities

CVE-2016-20030 — Critical (CVSS 9.8): ZKTeco ZKBioSecurity 3.0 contains a user enumeration vulnerability that allows unauthenticated attackers to discover…
CVE-2026-16102 — High (CVSS 8.1): A flaw was found in the Dynamic Client Registration (DCR) component of Keycloak, an identity and access management…
CVE-2026-15573 — High (CVSS 8.1): A flaw was found in Keycloak's Authorization Services. The component responsible for matching request paths to security…
CVE-2026-4636 — High (CVSS 8.1): A flaw was found in Keycloak. An authenticated user with the uma_protection role can bypass User-Managed Access (UMA)…
CVE-2026-89060 — High (CVSS 7.7): A cross-namespace authorization flaw in multicluster-observability-addon allows a user with permission to modify a…
CVE-2026-57920 — High (CVSS 7.7): Peplink InControl 2 through 2.14.2 before 2026-06-03 allows use of a semicolon to bypass access-control rules for…

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