CVE-2026-6276CWE-319CWE-346

CVE-2026-6276

High · published May 13, 2026

CVSS v3.1
7.5
EPSS
0%
Percentile
27.3
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.00349 · 27.3th percentile
Weaknesses
CWE-319 · Cleartext Transmission of Sensitive Information; CWE-346 · Origin Validation Error
Published
2026-05-13T17:01Z
Affected products (1)
ProductVersionsFixed in
haxx/curl≥ 7.71.0, < 8.20.08.20.0
References (5)
EPSS history
Timeline
  • 13 MAY 08:28Z
    stale custom cookie host causes cookie leak
    cvelistv5