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TI-2026-77123 Aliases CVE-2026-86411GHSA-533v-mrfx-494r

FTP connection reuse in curl inherits client certificate identity

Priority HIGH 74CWE-488Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · High · None
Fix status
Partial Red Hat: 1 fixed, 1 without a fix

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat.

Summary

curl version 8.21.0 is affected. An ftp:// transfer configured with CURLUSESSL_NONE can reuse a pooled FTP control connection that an earlier handle upgraded with STARTTLS and authenticated with a client certificate, so the server keeps authorizing the new transfer under that certificate identity. A remote attacker with no privileges and no user interaction can exploit this, and the flaw is classified as CWE-488.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

An `ftp://` transfer configured with `CURLUSESSL_NONE` can reuse a pooled FTP control connection that a previous easy handle upgraded with `STARTTLS` and authenticated using a client certificate. The second handle performs neither a new TLS handshake nor a new FTP login, so the server continues to authorize it under the first handle's certificate identity.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00433 37th percentileScored 2026-11-07
Fix Partial Red Hat: 1 advisoryRed Hat: 1 fixed, 1 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
curlcurl8.21.0 – 8.21.0—No fix listedCNA
  • curl Vendorcurl Affected 8.21.0 – 8.21.0 Fixed in — No fix listed CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*——Haxx
  • cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:* Versions — — ·Haxx

Remediation

The sources list no fixed version for curl. Red Hat Hardened Images is fixed by RHSA-2026:82895, released 2026-10-14. Red Hat lists no available fix plan for Red Hat Satellite 6.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Red Hat 1 advisory

  • RHSA-2026:82895 Released 2026-10-14 · Red Hat rating Important
    Red 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 →

ProductStatusPlan or fix
Red Hat Satellite 6AffectedNo fix yet: Fix deferred
Red Hat Hardened ImagesFixed 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

  1. 2026-10-21 Threatist record created from CVE-2026-86411
  2. 2026-10-21 Alias added: GHSA-533v-mrfx-494r
  3. 2026-10-29 CVSS score added · CISA ADP
  4. 2026-10-29 Weakness changed · CISA ADP
  5. 2026-10-29 CISA SSVC decision points changed
  6. 2026-10-29 Priority changed: LOW → HIGH

References

Other 3

See all 103 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences