CVE-2026-8927: env-set cross-proxy Digest auth state leak

Critical severity · published Jul 3, 2026

CVE-2026-8927

env-set cross-proxy Digest auth state leak

9.1

CVSS

0.5%

EPSS

On KEV

Description

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`.

CVSS vector

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

Attack vector

Network

Complexity

Low

Privileges

None

User interaction

None

Confidentiality

High

Integrity

High

Availability

None

Scope

Unchanged

Exploitation

Is it being used?

Exploit prediction (EPSS)0.5% · higher than 43% of CVEs

Exploited in the wildNo evidence yet

CISA KEVNot listed

Ransomware campaign useNot known

Affected products

Which versions

curl · curl

7.12.0 before 8.14.2; 8.15.0 before 8.16.1; 8.17.0 before 8.20.1; fc6eff13b5414caf6edf22d73a3239e074a04216 before 5c225384b8d52c67ce8259c6e4203bc57aacb567; 8.20.0; 8.19.0; +34 more · source: vendor, NVD

In the news

VulnerabilityHigh

Hitachi Energy RTU500 Product

View CSAF Summary Hitachi Energy is aware of vulnerabilities that affect RTU500 product versions listed in this document. These vulnerabilities if exploited can have impact on confidentiality, integrity and availability of the product. Please refer to the Recommended Immediate Actions for information about the mitigation/remediation. The following versions of Hitachi Energy RTU500 Product are affected: RTU500 series CMU Firmware vers:RTU500_series_CMU_Firmware/>=13.5.1|<=13.5.4, vers:RTU500_series_CMU_Firmware/>=13.6.1|<=13.6.3, vers:RTU500_series_CMU_Firmware/>=13.7.1|<=13.7.8, vers:RTU500_series_CMU_Firmware/>=13.8.1|<=13.8.2, vers:RTU500_series_CMU_Firmware/>=12.7.1|<=12.7.7 (CVE-2026-17539, CVE-2026-28388, CVE-2026-6732, CVE-2026-6653, CVE-2026-6276, CVE-2026-9079, CVE-2026-11856, CVE-2026-8927, CVE-2026-8932, CVE-2026-17539, CVE-2026-28388, CVE-2026-6732, CVE-2026-6653, CVE-2026-6276, CVE-2026-9079, CVE-2026-11856, CVE-2026-8927, CVE-2026-8932, CVE-2026-17539, CVE-2026-28388, CVE-2026-6732, CVE-2026-6653, CVE-2026-6276, CVE-2026-9079, CVE-2026-11856, CVE-2026-8927, CVE-2026-8932, CVE-2026-17539, CVE-2026-28388, CVE-2026-6732, CVE-2026-6653, CVE-2026-6276, CVE-2026-9079, CVE-2026-11856, CVE-2026-8927, CVE-2026-8932, CVE-2026-17539, CVE-2026-28388, CVE-2026-6653) CVSS Vendor Equipment v3 8.8 Hitachi Energy RTU500 series CMU Firmware 7 Vulnerabilities NULL Pointer Dereference, ...

CVE-2026-17539 CVE-2026-28388 CVE-2026-6732

Oct 20, 2026·US-CERT ICS Advisories

Affected product

curl

All curl CVEs

References

NVD

https://nvd.nist.gov/vuln/detail/CVE-2026-8927

CVE.org

https://www.cve.org/CVERecord?id=CVE-2026-8927

Patch

https://curl.se/docs/CVE-2026-8927.html

Vendor Advisory

https://curl.se/docs/CVE-2026-8927.json

Exploit

https://hackerone.com/reports/3744543