TI-2026-77127 Aliases CVE-2026-86415 GHSA-4g5c-8qrq-wcmw

curl reuses cached Schannel connection for redirected transfers

LOW 39CWE-201Published 2026-10-20 · Updated 2026-10-30

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Information disclosure
Confidentiality · integrity · availability: None · High · None
Fix status: No fix listed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-201.

Summary

curl 8.21.0 and 8.22.0 are affected. The connection cache match function ignores the automatic client certificate option, so a cached, already authenticated Schannel connection can be handed to a transfer that was redirected to a different origin (CWE-201). A remote attacker needs no privileges or user interaction and can affect the integrity of the transferred data.

Written with Claude Haiku 5.5 from the sources below · 2026-10-30

Description from the CNA

libcurl's connection cache match function never considers the automatic client certificate option, so a cached, already authenticated Schannel connection can be handed to a transfer that got redirected to a different origin, even though the code explicitly switched off the auto client cert option for that transfer to prevent exactly this.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00419 36th percentileScored 2026-11-07

Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: Yes
Technical impact: Partial

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

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
curl	curl	8.22.0 – 8.22.0; 8.21.0 – 8.21.0	—	No fix listed	CNA

curl Vendorcurl Affected 8.22.0 – 8.22.0; 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.

CPE	Versions	Role	Vendor
cpe:2.3:a:haxx:curl::::::::	—	—	Haxx

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

Remediation

The sources list no fixed version for curl.

Written with Claude Haiku 5.5 from the sources below · 2026-10-30

Vendor assessments

Red Hat

Red Hat rating: Low. Red Hat's page for this CVE →

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-2026-86415
2026-10-21 Alias added: GHSA-4g5c-8qrq-wcmw
2026-10-30 CVSS score added · CISA ADP
2026-10-30 Weakness changed · CISA ADP
2026-10-30 CISA SSVC decision points changed

References

Other 3

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

See all 103 →

Sources

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