How severe is CVE-2026-44503?

CVE-2026-44503 has a CVSS 4.0 base score of 7.0, rated high severity.

Is CVE-2026-44503 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (39th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-44503?

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.

Does CVE-2026-44503 have an EU (EUVD) identifier?

Yes. CVE-2026-44503 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30323.

When was CVE-2026-44503 published?

CVE-2026-44503 was published on 2026-05-14 and last updated on 2026-06-17.

CVE-2026-44503

CVE-2026-44503 is a high-severity vulnerability with a CVSS 4.0 base score of 7.0. 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-601.

Key facts

Severity: High (CVSS 4.0 base score 7.0)
EPSS exploit prediction: 1% (39th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-30323
Weakness: CWE-601
Published: 2026-05-14
Last modified: 2026-06-17

Description

The RedirectHandler middleware in microsoft/kiota-java (com.microsoft.kiota:microsoft-kiota-http-okHttp v1.9.0) and other Kiota libraries fails to strip sensitive HTTP headers when following 3xx redirects to a different host or scheme. Only the Authorization header is removed; Cookie, Proxy-Authorization, and all custom headers are forwarded to the redirect target.

Frequently asked questions

What is CVE-2026-44503?: The RedirectHandler middleware in microsoft/kiota-java (com.microsoft.kiota:microsoft-kiota-http-okHttp v1.9.0) and other Kiota libraries fails to strip sensitive HTTP headers when following 3xx redirects to a different host or scheme. Only the Authorization header is removed; Cookie, Proxy-Authorization, and all custom headers are forwarded to the redirect target.
How severe is CVE-2026-44503?: CVE-2026-44503 has a CVSS 4.0 base score of 7.0, rated high severity.
Is CVE-2026-44503 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (39th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-44503?: 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.
Does CVE-2026-44503 have an EU (EUVD) identifier?: Yes. CVE-2026-44503 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30323.
When was CVE-2026-44503 published?: CVE-2026-44503 was published on 2026-05-14 and last updated on 2026-06-17.

References

https://github.com/microsoft/kiota-java/security/advisories/GHSA-7j59-v9qr-6fq9

Other CWE-601 (Open Redirect) vulnerabilities

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