CVE-2026-11564

EUVD-2026-41499
libcurl keeps previously used connections in a connection pool for subsequent
transfers to reuse if one of them matches the setup.

An easy handle that first uses default native CA trust can continue trusting
the native platform store after the application switches that same handle to
custom CA material for a later transfer.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
curlCNA
9.1 CRITICAL
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: 29.42%
Affected Products (NVD)
VendorProductVersion
haxxcurl
8.17.0 ≤
𝑥
< 8.21.0
𝑥
= Vulnerable software versions
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
curlcurl
𝑥
≤ 8.20.0
CNA
curlcurl
𝑥
≤ 8.19.0
CNA
curlcurl
𝑥
≤ 8.18.0
CNA
curlcurl
𝑥
≤ 8.17.0
CNA
Debian logo
Debian Releases
Debian Product
Codename
curl
bookworm
7.88.1-10+deb12u15
fixed
bookworm (security)
7.88.1-10+deb12u5
fixed
bullseye
7.74.0-1.3+deb11u13
fixed
bullseye (security)
7.74.0-1.3+deb11u16
fixed
forky
8.21.0-2
fixed
sid
8.21.0-2
fixed
trixie
8.14.1-2+deb13u4
fixed
Ubuntu logo
Ubuntu Releases
Ubuntu Product
Codename
curl
bionic
not-affected
focal
not-affected
jammy
not-affected
noble
not-affected
questing
not-affected
resolute
Fixed 8.18.0-1ubuntu2.3
released
trusty
not-affected
xenial
not-affected
Common Weakness Enumeration
Vulnerability Media Exposure
References
https://curl.se/docs/CVE-2026-11564.html
https://curl.se/docs/CVE-2026-11564.json
https://hackerone.com/reports/3788984
https://hackerone.com/reports/3788984