Credential leak in curl redirects to URLs with userinfo
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- High · High · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat. Impact type from CWE-200.
Summary
curl 8.21.0 and 8.22.0 are affected. When following an HTTP redirect to a URL that contains userinfo, curl keeps and resends the original host's HTTP Negotiate authentication state, exposing sensitive information (CWE-200). A remote malicious server can trigger such a redirect without authentication or user interaction, making curl send a freshly minted Kerberos ticket from the client's identity to an untrusted third-party host.
Written with Claude Haiku 5.5 from the sources below · 2026-10-30
Description from the CNA
When processing an HTTP redirect to a URL containing userinfo (a `username:password` component), curl might erroneously retain and re-transmit the original host's HTTP Negotiate authentication state. Consequently, a malicious server can trigger a redirect containing arbitrary userinfo to force curl to send a freshly minted Kerberos ticket—generated using the ambient identity of the client process to an untrusted third-party host, effectively bypassing the domain-scoping restrictions normally enforced by the absence of `--location-trusted`.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
The sources list no fixed version for curl.
Written with Claude Haiku 5.5 from the sources below · 2026-10-30
Red Hat 1 advisory
- RHSA-2026:82895 Released 2026-10-14 · Red Hat rating ImportantRed Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images curl-8.23.0-0.1.hum1@aarch64, curl-8.23.0-0.1.hum1@s390x, curl-8.23.0-0.1.hum1@src +10
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Hardened Images | Fixed | RHSA-2026:82895 |
Not affected: 9 products
- Confidential Compute Attestation
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat Hardened Images
- Red Hat JBoss Core Services
- Red Hat Satellite 6
Timeline
- 2026-10-21 Threatist record created from CVE-2026-94265
- 2026-10-21 Alias added: GHSA-qqmr-6r9w-pmx5
- 2026-10-30 CVSS score added · CISA ADP
- 2026-10-30 Weakness changed · CISA ADP
- 2026-10-30 CISA SSVC decision points changed
- 2026-10-30 Priority changed: LOW → HIGH
- 2026-10-31 EPSS moved to the 50th–90th percentile
More curl vulnerabilities
- TI-2023-19922 Out-of-bounds write in curl CVSS 3.1CRITICAL 9.8
- TI-2026-16162 Negotiate ambient user conn reuse CVSS 3.1CRITICAL 9.8
- TI-2026-10231 cross-origin Digest auth state leak CVSS 3.1CRITICAL 9.8
- TI-2026-09063 HTTP/2 stream-dependency tree UAF CVSS 3.1CRITICAL 9.8
- TI-2026-07976 stale proxy password leak CVSS 3.1CRITICAL 9.8
- TI-2026-07845 SASL double-free CVSS 3.1CRITICAL 9.8
Sources
- CVE-2026-94265 · CVE Program
- CVE-2026-94265 · NVD
- FIRST EPSS
- GHSA-qqmr-6r9w-pmx5 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-94265 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences