CVE-2026-11856 - Vulnerability Details

Description

Successfully using libcurl to do a transfer to a specific HTTP origin
(`hostA`) with **Digest** authentication and then changing the origin to a
different one (`hostB`) for a second transfer, reusing the same handle, makes
libcurl wrongly pass on the `Authorization:` header field meant for `hostA`,
to `hostB`.

Published: 2026-07-03

Score: 9.8 Critical

EPSS: < 1% Very Low

KEV: No

Impact:

Action:

Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

curl

unaffected

Version	Status	Constraints
`8.20.0`	affected	≤ 8.20.0
`8.19.0`	affected	≤ 8.19.0
`8.18.0`	affected	≤ 8.18.0
`8.17.0`	affected	≤ 8.17.0
`8.16.0`	affected	≤ 8.16.0
`8.15.0`	affected	≤ 8.15.0
`8.14.1`	affected	≤ 8.14.1
`8.14.0`	affected	≤ 8.14.0
`8.13.0`	affected	≤ 8.13.0
`8.12.1`	affected	≤ 8.12.1
`8.12.0`	affected	≤ 8.12.0
`8.11.1`	affected	≤ 8.11.1
`8.11.0`	affected	≤ 8.11.0
`8.10.1`	affected	≤ 8.10.1
`8.10.0`	affected	≤ 8.10.0
`8.9.1`	affected	≤ 8.9.1
`8.9.0`	affected	≤ 8.9.0
`8.8.0`	affected	≤ 8.8.0
`8.7.1`	affected	≤ 8.7.1
`8.7.0`	affected	≤ 8.7.0
`8.6.0`	affected	≤ 8.6.0
`8.5.0`	affected	≤ 8.5.0
`8.4.0`	affected	≤ 8.4.0
`8.3.0`	affected	≤ 8.3.0
`8.2.1`	affected	≤ 8.2.1
`8.2.0`	affected	≤ 8.2.0
`8.1.2`	affected	≤ 8.1.2
`8.1.1`	affected	≤ 8.1.1
`8.1.0`	affected	≤ 8.1.0
`8.0.1`	affected	≤ 8.0.1
`8.0.0`	affected	≤ 8.0.0
`7.88.1`	affected	≤ 7.88.1
`7.88.0`	affected	≤ 7.88.0
`7.87.0`	affected	≤ 7.87.0
`7.86.0`	affected	≤ 7.86.0
`7.85.0`	affected	≤ 7.85.0
`7.84.0`	affected	≤ 7.84.0
`7.83.1`	affected	≤ 7.83.1
`7.83.0`	affected	≤ 7.83.0
`7.82.0`	affected	≤ 7.82.0
`7.81.0`	affected	≤ 7.81.0
`7.80.0`	affected	≤ 7.80.0
`7.79.1`	affected	≤ 7.79.1
`7.79.0`	affected	≤ 7.79.0
`7.78.0`	affected	≤ 7.78.0
`7.77.0`	affected	≤ 7.77.0
`7.76.1`	affected	≤ 7.76.1
`7.76.0`	affected	≤ 7.76.0
`7.75.0`	affected	≤ 7.75.0
`7.74.0`	affected	≤ 7.74.0
`7.73.0`	affected	≤ 7.73.0
`7.72.0`	affected	≤ 7.72.0
`7.71.1`	affected	≤ 7.71.1
`7.71.0`	affected	≤ 7.71.0
`7.70.0`	affected	≤ 7.70.0
`7.69.1`	affected	≤ 7.69.1
`7.69.0`	affected	≤ 7.69.0
`7.68.0`	affected	≤ 7.68.0
`7.67.0`	affected	≤ 7.67.0
`7.66.0`	affected	≤ 7.66.0
`7.65.3`	affected	≤ 7.65.3
`7.65.2`	affected	≤ 7.65.2
`7.65.1`	affected	≤ 7.65.1
`7.65.0`	affected	≤ 7.65.0
`7.64.1`	affected	≤ 7.64.1
`7.64.0`	affected	≤ 7.64.0
`7.63.0`	affected	≤ 7.63.0
`7.62.0`	affected	≤ 7.62.0
`7.61.1`	affected	≤ 7.61.1
`7.61.0`	affected	≤ 7.61.0
`7.60.0`	affected	≤ 7.60.0
`7.59.0`	affected	≤ 7.59.0
`7.58.0`	affected	≤ 7.58.0
`7.57.0`	affected	≤ 7.57.0
`7.56.1`	affected	≤ 7.56.1
`7.56.0`	affected	≤ 7.56.0
`7.55.1`	affected	≤ 7.55.1
`7.55.0`	affected	≤ 7.55.0
`7.54.1`	affected	≤ 7.54.1
`7.54.0`	affected	≤ 7.54.0
`7.53.1`	affected	≤ 7.53.1
`7.53.0`	affected	≤ 7.53.0
`7.52.1`	affected	≤ 7.52.1
`7.52.0`	affected	≤ 7.52.0
`7.51.0`	affected	≤ 7.51.0
`7.50.3`	affected	≤ 7.50.3
`7.50.2`	affected	≤ 7.50.2
`7.50.1`	affected	≤ 7.50.1
`7.50.0`	affected	≤ 7.50.0
`7.49.1`	affected	≤ 7.49.1
`7.49.0`	affected	≤ 7.49.0
`7.48.0`	affected	≤ 7.48.0
`7.47.1`	affected	≤ 7.47.1
`7.47.0`	affected	≤ 7.47.0
`7.46.0`	affected	≤ 7.46.0
`7.45.0`	affected	≤ 7.45.0
`7.44.0`	affected	≤ 7.44.0
`7.43.0`	affected	≤ 7.43.0
`7.42.1`	affected	≤ 7.42.1
`7.42.0`	affected	≤ 7.42.0
`7.41.0`	affected	≤ 7.41.0
`7.40.0`	affected	≤ 7.40.0
`7.39.0`	affected	≤ 7.39.0
`7.38.0`	affected	≤ 7.38.0
`7.37.1`	affected	≤ 7.37.1
`7.37.0`	affected	≤ 7.37.0
`7.36.0`	affected	≤ 7.36.0
`7.35.0`	affected	≤ 7.35.0
`7.34.0`	affected	≤ 7.34.0
`7.33.0`	affected	≤ 7.33.0
`7.32.0`	affected	≤ 7.32.0
`7.31.0`	affected	≤ 7.31.0
`7.30.0`	affected	≤ 7.30.0
`7.29.0`	affected	≤ 7.29.0
`7.28.1`	affected	≤ 7.28.1
`7.28.0`	affected	≤ 7.28.0
`7.27.0`	affected	≤ 7.27.0
`7.26.0`	affected	≤ 7.26.0
`7.25.0`	affected	≤ 7.25.0
`7.24.0`	affected	≤ 7.24.0
`7.23.1`	affected	≤ 7.23.1
`7.23.0`	affected	≤ 7.23.0
`7.22.0`	affected	≤ 7.22.0
`7.21.7`	affected	≤ 7.21.7
`7.21.6`	affected	≤ 7.21.6
`7.21.5`	affected	≤ 7.21.5
`7.21.4`	affected	≤ 7.21.4
`7.21.3`	affected	≤ 7.21.3
`7.21.2`	affected	≤ 7.21.2
`7.21.1`	affected	≤ 7.21.1
`7.21.0`	affected	≤ 7.21.0
`7.20.1`	affected	≤ 7.20.1
`7.20.0`	affected	≤ 7.20.0
`7.19.7`	affected	≤ 7.19.7
`7.19.6`	affected	≤ 7.19.6
`7.19.5`	affected	≤ 7.19.5
`7.19.4`	affected	≤ 7.19.4
`7.19.3`	affected	≤ 7.19.3
`7.19.2`	affected	≤ 7.19.2
`7.19.1`	affected	≤ 7.19.1
`7.19.0`	affected	≤ 7.19.0
`7.18.2`	affected	≤ 7.18.2
`7.18.1`	affected	≤ 7.18.1
`7.18.0`	affected	≤ 7.18.0
`7.17.1`	affected	≤ 7.17.1
`7.17.0`	affected	≤ 7.17.0
`7.16.4`	affected	≤ 7.16.4
`7.16.3`	affected	≤ 7.16.3
`7.16.2`	affected	≤ 7.16.2
`7.16.1`	affected	≤ 7.16.1
`7.16.0`	affected	≤ 7.16.0
`7.15.5`	affected	≤ 7.15.5
`7.15.4`	affected	≤ 7.15.4
`7.15.3`	affected	≤ 7.15.3
`7.15.2`	affected	≤ 7.15.2
`7.15.1`	affected	≤ 7.15.1
`7.15.0`	affected	≤ 7.15.0
`7.14.1`	affected	≤ 7.14.1
`7.14.0`	affected	≤ 7.14.0
`7.13.2`	affected	≤ 7.13.2
`7.13.1`	affected	≤ 7.13.1
`7.13.0`	affected	≤ 7.13.0
`7.12.3`	affected	≤ 7.12.3
`7.12.2`	affected	≤ 7.12.2
`7.12.1`	affected	≤ 7.12.1
`7.12.0`	affected	≤ 7.12.0
`7.11.2`	affected	≤ 7.11.2
`7.11.1`	affected	≤ 7.11.1
`7.11.0`	affected	≤ 7.11.0
`7.10.8`	affected	≤ 7.10.8
`7.10.7`	affected	≤ 7.10.7
`7.10.6`	affected	≤ 7.10.6

Configuration 1 [-]

cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*

Package	CPE	Advisory	Released Date
Red Hat Hardened Images
rust-main-1.96.1-1.hum1	cpe:/a:redhat:hummingbird:1	RHSA-2026:34975	2026-07-02T00:00:00Z

Vendor Product Confidence Versions

Curl

100%

Version	Status	Scheme	Platform
`8.20.0`	affected	semver	—
`8.19.0`	affected	semver	—
`8.18.0`	affected	semver	—
`8.17.0`	affected	semver	—
`8.16.0`	affected	semver	—
`8.15.0`	affected	semver	—
`8.14.1`	affected	semver	—
`8.14.0`	affected	semver	—
`8.13.0`	affected	semver	—
`8.12.1`	affected	semver	—
`8.12.0`	affected	semver	—
`8.11.1`	affected	semver	—
`8.11.0`	affected	semver	—
`8.10.1`	affected	semver	—
`8.10.0`	affected	semver	—
`8.9.1`	affected	semver	—
`8.9.0`	affected	semver	—
`8.8.0`	affected	semver	—
`8.7.1`	affected	semver	—
`8.7.0`	affected	semver	—
`8.6.0`	affected	semver	—
`8.5.0`	affected	semver	—
`8.4.0`	affected	semver	—
`8.3.0`	affected	semver	—
`8.2.1`	affected	semver	—
`8.2.0`	affected	semver	—
`8.1.2`	affected	semver	—
`8.1.1`	affected	semver	—
`8.1.0`	affected	semver	—
`8.0.1`	affected	semver	—
`8.0.0`	affected	semver	—
`7.88.1`	affected	semver	—
`7.88.0`	affected	semver	—
`7.87.0`	affected	semver	—
`7.86.0`	affected	semver	—
`7.85.0`	affected	semver	—
`7.84.0`	affected	semver	—
`7.83.1`	affected	semver	—
`7.83.0`	affected	semver	—
`7.82.0`	affected	semver	—
`7.81.0`	affected	semver	—
`7.80.0`	affected	semver	—
`7.79.1`	affected	semver	—
`7.79.0`	affected	semver	—
`7.78.0`	affected	semver	—
`7.77.0`	affected	semver	—
`7.76.1`	affected	semver	—
`7.76.0`	affected	semver	—
`7.75.0`	affected	semver	—
`7.74.0`	affected	semver	—
`7.73.0`	affected	semver	—
`7.72.0`	affected	semver	—
`7.71.1`	affected	semver	—
`7.71.0`	affected	semver	—
`7.70.0`	affected	semver	—
`7.69.1`	affected	semver	—
`7.69.0`	affected	semver	—
`7.68.0`	affected	semver	—
`7.67.0`	affected	semver	—
`7.66.0`	affected	semver	—
`7.65.3`	affected	semver	—
`7.65.2`	affected	semver	—
`7.65.1`	affected	semver	—
`7.65.0`	affected	semver	—
`7.64.1`	affected	semver	—
`7.64.0`	affected	semver	—
`7.63.0`	affected	semver	—
`7.62.0`	affected	semver	—
`7.61.1`	affected	semver	—
`7.61.0`	affected	semver	—
`7.60.0`	affected	semver	—
`7.59.0`	affected	semver	—
`7.58.0`	affected	semver	—
`7.57.0`	affected	semver	—
`7.56.1`	affected	semver	—
`7.56.0`	affected	semver	—
`7.55.1`	affected	semver	—
`7.55.0`	affected	semver	—
`7.54.1`	affected	semver	—
`7.54.0`	affected	semver	—
`7.53.1`	affected	semver	—
`7.53.0`	affected	semver	—
`7.52.1`	affected	semver	—
`7.52.0`	affected	semver	—
`7.51.0`	affected	semver	—
`7.50.3`	affected	semver	—
`7.50.2`	affected	semver	—
`7.50.1`	affected	semver	—
`7.50.0`	affected	semver	—
`7.49.1`	affected	semver	—
`7.49.0`	affected	semver	—
`7.48.0`	affected	semver	—
`7.47.1`	affected	semver	—
`7.47.0`	affected	semver	—
`7.46.0`	affected	semver	—
`7.45.0`	affected	semver	—
`7.44.0`	affected	semver	—
`7.43.0`	affected	semver	—
`7.42.1`	affected	semver	—
`7.42.0`	affected	semver	—
`7.41.0`	affected	semver	—
`7.40.0`	affected	semver	—
`7.39.0`	affected	semver	—
`7.38.0`	affected	semver	—
`7.37.1`	affected	semver	—
`7.37.0`	affected	semver	—
`7.36.0`	affected	semver	—
`7.35.0`	affected	semver	—
`7.34.0`	affected	semver	—
`7.33.0`	affected	semver	—
`7.32.0`	affected	semver	—
`7.31.0`	affected	semver	—
`7.30.0`	affected	semver	—
`7.29.0`	affected	semver	—
`7.28.1`	affected	semver	—
`7.28.0`	affected	semver	—
`7.27.0`	affected	semver	—
`7.26.0`	affected	semver	—
`7.25.0`	affected	semver	—
`7.24.0`	affected	semver	—
`7.23.1`	affected	semver	—
`7.23.0`	affected	semver	—
`7.22.0`	affected	semver	—
`7.21.7`	affected	semver	—
`7.21.6`	affected	semver	—
`7.21.5`	affected	semver	—
`7.21.4`	affected	semver	—
`7.21.3`	affected	semver	—
`7.21.2`	affected	semver	—
`7.21.1`	affected	semver	—
`7.21.0`	affected	semver	—
`7.20.1`	affected	semver	—
`7.20.0`	affected	semver	—
`7.19.7`	affected	semver	—
`7.19.6`	affected	semver	—
`7.19.5`	affected	semver	—
`7.19.4`	affected	semver	—
`7.19.3`	affected	semver	—
`7.19.2`	affected	semver	—
`7.19.1`	affected	semver	—
`7.19.0`	affected	semver	—
`7.18.2`	affected	semver	—
`7.18.1`	affected	semver	—
`7.18.0`	affected	semver	—
`7.17.1`	affected	semver	—
`7.17.0`	affected	semver	—
`7.16.4`	affected	semver	—
`7.16.3`	affected	semver	—
`7.16.2`	affected	semver	—
`7.16.1`	affected	semver	—
`7.16.0`	affected	semver	—
`7.15.5`	affected	semver	—
`7.15.4`	affected	semver	—
`7.15.3`	affected	semver	—
`7.15.2`	affected	semver	—
`7.15.1`	affected	semver	—
`7.15.0`	affected	semver	—
`7.14.1`	affected	semver	—
`7.14.0`	affected	semver	—
`7.13.2`	affected	semver	—
`7.13.1`	affected	semver	—
`7.13.0`	affected	semver	—
`7.12.3`	affected	semver	—
`7.12.2`	affected	semver	—
`7.12.1`	affected	semver	—
`7.12.0`	affected	semver	—
`7.11.2`	affected	semver	—
`7.11.1`	affected	semver	—
`7.11.0`	affected	semver	—
`7.10.8`	affected	semver	—
`7.10.7`	affected	semver	—
`7.10.6`	affected	semver	—

Found an issue or want to improve our Enrichment? You can suggest it directly by opening an issue on our dedicated GitHub repository .

Remediation

No vendor fix or workaround currently provided.

Additional remediation guidance may be available on OpenCVE Cloud.

Tracking

Sign in to view the affected projects.

Advisories

No advisories yet.

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00604.

Exploitation poc

Automatable yes

Technical Impact total

References

Link	Providers
https://curl.se/docs/CVE-2026-11856.html
https://curl.se/docs/CVE-2026-11856.json
https://hackerone.com/reports/3793260
https://nvd.nist.gov/vuln/detail/CVE-2026-11856
https://www.cve.org/CVERecord?id=CVE-2026-11856

History

Thu, 09 Jul 2026 00:30:00 +0000

Type	Values Removed	Values Added
Weaknesses	CWE-200

Thu, 09 Jul 2026 00:15:00 +0000

Type	Values Removed	Values Added
First Time appeared		Redhat Redhat hummingbird
Weaknesses		CWE-201
CPEs		cpe:/a:redhat:hummingbird:1
Vendors & Products		Redhat Redhat hummingbird
References		https://nvd.nist.gov/vuln/detail/CVE-2026-11856 https://www.cve.org/CVERecord?id=CVE-2026-11856
Metrics	threat_severity `None`	threat_severity `Moderate`

Wed, 08 Jul 2026 11:45:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-200

Wed, 08 Jul 2026 00:15:00 +0000

Type	Values Removed	Values Added
Weaknesses	CWE-200

Mon, 06 Jul 2026 19:30:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-200
Metrics		cvssV3_1 `{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}` ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}`

Mon, 06 Jul 2026 13:30:00 +0000

Type	Values Removed	Values Added
Weaknesses	CWE-200

Sun, 05 Jul 2026 05:00:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-200

Sat, 04 Jul 2026 17:30:00 +0000

Type	Values Removed	Values Added
Weaknesses	CWE-798

Sat, 04 Jul 2026 09:45:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-798

Sat, 04 Jul 2026 05:15:00 +0000

Type	Values Removed	Values Added
Weaknesses	CWE-200 CWE-639

Fri, 03 Jul 2026 10:45:00 +0000

Type	Values Removed	Values Added
First Time appeared		Curl Curl curl
Vendors & Products		Curl Curl curl

Fri, 03 Jul 2026 10:00:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-200 CWE-639

Fri, 03 Jul 2026 06:45:00 +0000

Type	Values Removed	Values Added
Description		Successfully using libcurl to do a transfer to a specific HTTP origin (`hostA`) with Digest authentication and then changing the origin to a different one (`hostB`) for a second transfer, reusing the same handle, makes libcurl wrongly pass on the `Authorization:` header field meant for `hostA`, to `hostB`.
Title		cross-origin Digest auth state leak
References		https://curl.se/docs/CVE-2026-11856.html https://curl.se/docs/CVE-2026-11856.json https://hackerone.com/reports/3793260

Subscriptions

Curl Curl

Haxx Curl

Redhat Hummingbird

MITRE

Status: PUBLISHED

Assigner: curl

Published: 2026-07-03T06:13:31.661Z

Updated: 2026-07-06T18:23:52.111Z

Reserved: 2026-06-10T08:59:16.646Z

Link: CVE-2026-11856

Vulnrichment

Updated: 2026-07-06T18:23:29.315Z

NVD

Status : Analyzed

Published: 2026-07-03T07:16:23.973

Modified: 2026-07-07T19:43:55.600

Link: CVE-2026-11856

Redhat

Severity : Moderate

Publid Date: 2026-07-03T06:13:31Z

Links: CVE-2026-11856 - Bugzilla

OpenCVE Enrichment

Updated: 2026-08-12T01:15:17Z

Weaknesses

Tracking

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

Exploitation poc

Automatable yes

Technical Impact total

Subscriptions

JSON object

JSON object

JSON object

JSON object

JSON object