TI-2026-77262 Aliases CVE-2026-87861 GHSA-34qg-cqjx-hpwx

Cross-origin reuse of a Negotiate connection in curl

HIGH 80CWE-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: 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-201.

Summary

When ambient user credentials are used, curl can send an HTTP request for one origin over a connection previously authenticated via Negotiate for a different origin, so the request's intended credentials go unused. The weakness is CWE-201, Insertion of Sensitive Information Into Sent Data, and affected versions are curl 8.21.0 and 8.22.0. The CVSS 3.1 base score is 9.1 (Critical), with vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N. CISA SSVC rates exploitation as poc, automatable as yes, and technical impact as total, and the issue is not in CISA KEV.

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

Description from the CNA

When using ambient user credentials, an HTTP request directed to one origin may be dispatched over a connection previously authenticated via Negotiate for a different origin, leaving the request's intended credentials unused.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.00676 52nd percentileScored 2026-11-07

Fix Fixed Red Hat: 1 advisory

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

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

No fixed curl version is listed for 8.21.0 or 8.22.0. Red Hat fixed Red Hat Hardened Images in RHSA-2026:82895, released 2026-10-14, and rates the issue Low. Eight Red Hat products are not affected.

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 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 →

Product	Status	Plan or fix
Red Hat Hardened Images	Fixed	RHSA-2026:82895

Not affected: 8 products

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-2026-87861
2026-10-21 Alias added: GHSA-34qg-cqjx-hpwx
2026-10-22 Affected versions changed · Red Hat
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

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