Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| curl | curl | 8.17.0 – < 8.20.1, 8.20.0, 8.19.0, 8.18.0, 8.17.0 | 8.20.1 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | curl | 8.21.0~rc2-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.04 LTS | curl | 8.18.0-1ubuntu2.3 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Hardened Images 1 | curl +3 | 8.21.0-0.1.hum1 | RHSA-2026:29017 |
| Red Hat Hardened Images 1 | rust +18 | 1.96.1-1.hum1 | RHSA-2026:34975 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | curl | 8.22.0-150700.7.33.1 | SUSE-SU-2026:5068-1 |
| SLES 15 SP6 | curl | 8.22.0-150600.4.58.1 | SUSE-SU-2026:5069-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 15 SP6 | curl | 8.22.0-150600.4.58.1 | SUSE-SU-2026:5069-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | curl | 8.21.0-1.1 | openSUSE-SU-2026:11230-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | curl | 8.21.0-r0 | — |
| Alpine v3.23 | curl | 8.22.0-r0 | — |
Advisories 6
- WID-SEC-2026-2052 cURL: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- SUSE-SU-2026:5069-1 Security update for curl SUSE / openSUSE Security Updates · Nov 3, 2026
- SUSE-SU-2026:5068-1 Security update for curl SUSE / openSUSE Security Updates · Nov 3, 2026
- RHSA-2026:34975 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- RHSA-2026:29017 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 17, 2026
- openSUSE-SU-2026:11230-1 curl-8.21.0-1.1 on GA media SUSE / openSUSE Security Updates · Jul 10, 2026