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© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2026-8927

39
FAUCET Score

When reusing a libcurl handle for sequential transfers driven by environment-variable proxy configuration, libcurl fails to clear the proxy authentication state between requests. Specifically, if the initial transfer authenticates against `proxyA` using Digest auth, a subsequent transfer routed through `proxyB` erroneously leaks the `Proxy-Authorization:` header intended solely for `proxyA`.

First published: Jul 3, 2026Last modified: Jul 3, 2026

Impacted Technologies

VendorProductVersion(s)CPE
>= 7.12.0, < 8.21.0CPE matchmatch criteria
cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*
>= 7.12.0, <= 7.12.0CPE match
cpe:2.3:a:curl:curl:*:*:*:*:*:*:*:*
>= 7.12.1, <= 7.12.1CPE match
cpe:2.3:a:curl:curl:*:*:*:*:*:*:*:*
>= 7.12.2, <= 7.12.2CPE match
cpe:2.3:a:curl:curl:*:*:*:*:*:*:*:*
>= 7.12.3, <= 7.12.3CPE match
cpe:2.3:a:curl:curl:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.1CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
5.2
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.44%
Probability of exploitation in next 30 days
EPSS Percentile
36.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0044 is in the 13th percentile among its peer group of 36,862 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (10)

microsoftpatch availablevia msrc
Product: azl3 curl 8.11.1-9 on Azure Linux 3.0Fixed in: 8.11.1-10
microsoftpatch availablevia msrc
Product: 21549-17084Fixed in: 8.11.1-10
ubuntupatch availablevia ubuntu_usn
Product: curl (focal)Fixed in: 7.68.0-1ubuntu2.25+esm4
ubuntupatch availablevia ubuntu_usn
Product: curl (jammy)Fixed in: 7.81.0-1ubuntu1.25
ubuntupatch availablevia ubuntu_usn
Product: curl (noble)Fixed in: 8.5.0-2ubuntu10.10
ubuntupatch availablevia ubuntu_usn
Product: curl (questing)Fixed in: 8.14.1-2ubuntu1.4
ubuntupatch availablevia ubuntu_usn
Product: curl (resolute)Fixed in: 8.18.0-1ubuntu2.2
ubuntupatch availablevia ubuntu_usn
Product: curl (trusty)Fixed in: 7.35.0-1ubuntu2.20+esm20
ubuntupatch availablevia ubuntu_usn
Product: curl (xenial)Fixed in: 7.47.0-1ubuntu2.19+esm16
ubuntupatch availablevia ubuntu_usn
Product: curl (bionic)Fixed in: 7.58.0-2ubuntu3.24+esm9

Vendor Advisories (2)

microsoft2026-Jul/CVE-2026-8927Moderate

env-set cross-proxy Digest auth state leak

Jul 2, 2026
ubuntuUSN-8487-1

curl vulnerabilities

Jun 30, 2026

References

curl.se / docs/CVE-2026-8927.html
PatchVendor Advisory
curl.se / docs/CVE-2026-8927.json
Vendor Advisory
hackerone.com / reports/3744543
ExploitIssue TrackingThird Party Advisory