CVE & CISA-KEV Catalog

CVE-2026-6276

MEDIUM
7.5
CVSS v3
NVD

Description

Using libcurl, when a custom `Host:` header is first set for an HTTP request and a second request is subsequently done using the same *easy handle* but without the custom `Host:` header set, the second request would use stale information and pass on cookies meant for the first host in the second request. Leak them.

CWE-319

How to fix

Remediation Available
curlDebian
Fixed in:8.20.0~rc3-1CVE-2026-6276
curlRocky
Fixed in:main@x86_64RHSA-2026:12916
Fixed in:main@aarch64RHSA-2026:12916
Fixed in:main@srcRHSA-2026:12916
curlRed Hat / RHEL
Fixed in:main@aarch64RHSA-2026:12916
Fixed in:main@srcRHSA-2026:12916
Fixed in:main@x86_64RHSA-2026:12916
curlUbuntu
Fixed in:7.81.0-1ubuntu1.24USN-8227-1
Fixed in:8.5.0-2ubuntu10.9USN-8227-1
Fixed in:8.14.1-2ubuntu1.3USN-8227-1
libcurl3-gnutlsUbuntu
Fixed in:7.81.0-1ubuntu1.24USN-8227-1
libcurl3-nssUbuntu
Fixed in:7.81.0-1ubuntu1.24USN-8227-1
libcurl3t64-gnutlsUbuntu
Fixed in:8.5.0-2ubuntu10.9USN-8227-1
Fixed in:8.14.1-2ubuntu1.3USN-8227-1
libcurl4Ubuntu
Fixed in:7.81.0-1ubuntu1.24USN-8227-1
libcurl4t64Ubuntu
Fixed in:8.5.0-2ubuntu10.9USN-8227-1
Fixed in:8.14.1-2ubuntu1.3USN-8227-1

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityNone
IntegrityNone
AvailabilityHigh

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

Exploit Intelligence

0.29%probability of exploitation in 30 days
21stpercentile

Low risk: more likely to be exploited than 21% of all known CVEs.

References

Patch1
Third-Party Advisory1
Product1
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-14.