# CVE-2026-8286: wrong STARTTLS connection reuse

CVE-2026-8286 is fixed in 16 products on 1 platform, first by curl 8.18.0-1ubuntu2.2, released June 26, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-8286
- Priority: High
- CVSS: 8.1 (Important)
- EPSS: 0.0031
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 26, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-8286

## Description

A vulnerability exists where a new transfer that uses STARTTLS to upgrade the connection might reuse an existing live connection even though the TLS configuration mismatches so it should not.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | curl Debian 13.5 (trixie) | 8.14.1-2+deb13u7 | [DEBIAN-CVE-2026-8286](https://patchblox.com/security/data/fix/linux/debian-cve-2026-8286.md) | Jul 24, 2026 |
| Linux | curl Debian 14 | 8.21.0~rc2-1 | [DEBIAN-CVE-2026-8286](https://patchblox.com/security/data/fix/linux/debian-cve-2026-8286.md) | Jul 24, 2026 |
| Linux | curl RHEL 10 | 8.12.1-1.el10_0.10 | [RHSA-2026:72506](https://patchblox.com/security/data/fix/linux/rhsa-2026-72506.md) | Jul 3, 2026 |
| Linux | curl RHEL 8 | 0:7.61.1-34.el8_10.13 | [RHSA-2026:57462](https://patchblox.com/security/data/fix/linux/rhsa-2026-57462.md) | Aug 20, 2026 |
| Linux | curl RHEL 9 | 0:7.76.1-40.el9_8.5 | [RHSA-2026:55439](https://patchblox.com/security/data/fix/linux/rhsa-2026-55439.md) | Aug 19, 2026 |
| Linux | curl Ubuntu 18.04.6 LTS (bionic) | 7.58.0-2ubuntu3.24+esm9 | [curl 7.58.0-2ubuntu3.24+esm9](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-curl-7.58.0-2ubuntu3.24-esm9.md) | Jul 3, 2026 |
| Linux | curl Ubuntu 20.04 LTS (focal) | 7.68.0-1ubuntu2.25+esm4 | [curl 7.68.0-1ubuntu2.25+esm4](https://patchblox.com/security/data/fix/linux/ubuntu-focal-curl-7.68.0-1ubuntu2.25-esm4.md) | Jul 3, 2026 |
| Linux | curl Ubuntu 22.04.1 LTS (jammy) | 7.81.0-1ubuntu1.25 | [curl 7.81.0-1ubuntu1.25](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-curl-7.81.0-1ubuntu1.25.md) | Jul 3, 2026 |
| Linux | curl Ubuntu 24.04.5 LTS (noble) | 8.5.0-2ubuntu10.10 | [curl 8.5.0-2ubuntu10.10](https://patchblox.com/security/data/fix/linux/ubuntu-noble-curl-8.5.0-2ubuntu10.10.md) | Jul 3, 2026 |
| Linux | curl Ubuntu 25.10 (questing) | 8.14.1-2ubuntu1.4 | [curl 8.14.1-2ubuntu1.4](https://patchblox.com/security/data/fix/linux/ubuntu-questing-curl-8.14.1-2ubuntu1.4.md) | Jul 3, 2026 |
| Linux | curl Ubuntu 26.04.1 LTS (resolute) | 8.18.0-1ubuntu2.2 | [curl 8.18.0-1ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-curl-8.18.0-1ubuntu2.2.md) | Jun 26, 2026 |
| Linux | curl almalinux 8 | 7.61.1-34.el8_10.13 | [ALSA-2026:57462](https://patchblox.com/security/data/fix/linux/alsa-2026-57462.md) | Aug 20, 2026 |
| Linux | curl almalinux 9 | 7.76.1-40.el9_8.5 | [ALSA-2026:55439](https://patchblox.com/security/data/fix/linux/alsa-2026-55439.md) | Aug 17, 2026 |
| Linux | curl amzn 2023 | 8.21.0-5.amzn2023.0.1 | [ALAS2023-2026-2132](https://patchblox.com/security/data/fix/linux/alas2023-2026-2132.md) | Sep 14, 2026 |
| Linux | curl ol 10 | 0:8.12.1-4.el10_2.4 | [ELSA-2026-55450](https://patchblox.com/security/data/fix/linux/elsa-2026-55450.md) | Aug 17, 2026 |
| Linux | curl ol 8 | 0:7.61.1-34.el8_10.13 | [ELSA-2026-57462](https://patchblox.com/security/data/fix/linux/elsa-2026-57462.md) | Aug 20, 2026 |
| Linux | curl ol 9 | 0:7.76.1-40.el9_8.5 | [ELSA-2026-55439](https://patchblox.com/security/data/fix/linux/elsa-2026-55439.md) | Aug 17, 2026 |
| Linux | curl opensuse-leap 16.0 | 8.14.1-160000.8.1 | [OPENSUSE-SU-2026:21272-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21272-1.md) | Jul 8, 2026 |
| Linux | curl rocky 8 | 0:7.61.1-34.el8_10.13 | [RLSA-2026:57462](https://patchblox.com/security/data/fix/linux/rlsa-2026-57462.md) | Aug 21, 2026 |
| Linux | curl rocky 9 | 0:7.76.1-40.el9_8.5 | [RLSA-2026:55439](https://patchblox.com/security/data/fix/linux/rlsa-2026-55439.md) | Aug 17, 2026 |
| Linux | curl sles 15.6 | 8.14.1-150600.4.46.1 | [SUSE-SU-2026:2926-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2926-1.md) | Jul 13, 2026 |
| Linux | curl sles 15.7 | 8.14.1-150700.7.20.1 | [SUSE-SU-2026:2925-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2925-1.md) | Jul 13, 2026 |
| Linux | curl sles 16.0 | 8.14.1-160000.8.1 | [SUSE-SU-2026:22582-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-22582-1.md) | Jul 8, 2026 |
| Linux | curl-debuginfo amzn 2023 | 8.21.0-5.amzn2023.0.1 | [ALAS2023-2026-2132](https://patchblox.com/security/data/fix/linux/alas2023-2026-2132.md) | Sep 14, 2026 |
| Linux | curl-debugsource amzn 2023 | 8.21.0-5.amzn2023.0.1 | [ALAS2023-2026-2132](https://patchblox.com/security/data/fix/linux/alas2023-2026-2132.md) | Sep 14, 2026 |
| Linux | curl-mini sles 16.0 | 8.14.1-160000.8.1 | [SUSE-SU-2026:22582-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-22582-1.md) | Jul 8, 2026 |
| Linux | curl-minimal RHEL 9 | 0:7.76.1-40.el9_8.5 | [RHSA-2026:55439](https://patchblox.com/security/data/fix/linux/rhsa-2026-55439.md) | Aug 19, 2026 |
| Linux | curl-minimal almalinux 9 | 7.76.1-40.el9_8.5 | [ALSA-2026:55439](https://patchblox.com/security/data/fix/linux/alsa-2026-55439.md) | Aug 17, 2026 |
| Linux | curl-minimal amzn 2023 | 8.21.0-5.amzn2023.0.1 | [ALAS2023-2026-2132](https://patchblox.com/security/data/fix/linux/alas2023-2026-2132.md) | Sep 14, 2026 |
| Linux | curl-minimal ol 9 | 0:7.76.1-40.el9_8.5 | [ELSA-2026-55439](https://patchblox.com/security/data/fix/linux/elsa-2026-55439.md) | Aug 17, 2026 |
| Linux | curl-minimal-debuginfo amzn 2023 | 8.21.0-5.amzn2023.0.1 | [ALAS2023-2026-2132](https://patchblox.com/security/data/fix/linux/alas2023-2026-2132.md) | Sep 14, 2026 |
| Linux | libcurl RHEL 8 | 0:7.61.1-34.el8_10.13 | [RHSA-2026:57462](https://patchblox.com/security/data/fix/linux/rhsa-2026-57462.md) | Aug 20, 2026 |
| Linux | libcurl RHEL 9 | 0:7.76.1-40.el9_8.5 | [RHSA-2026:55439](https://patchblox.com/security/data/fix/linux/rhsa-2026-55439.md) | Aug 19, 2026 |
| Linux | libcurl almalinux 8 | 7.61.1-34.el8_10.13 | [ALSA-2026:57462](https://patchblox.com/security/data/fix/linux/alsa-2026-57462.md) | Aug 20, 2026 |
| Linux | libcurl almalinux 9 | 7.76.1-40.el9_8.5 | [ALSA-2026:55439](https://patchblox.com/security/data/fix/linux/alsa-2026-55439.md) | Aug 17, 2026 |
| Linux | libcurl amzn 2023 | 8.21.0-5.amzn2023.0.1 | [ALAS2023-2026-2132](https://patchblox.com/security/data/fix/linux/alas2023-2026-2132.md) | Sep 14, 2026 |
| Linux | libcurl ol 10 | 0:8.12.1-4.el10_2.4 | [ELSA-2026-55450](https://patchblox.com/security/data/fix/linux/elsa-2026-55450.md) | Aug 17, 2026 |
| Linux | libcurl ol 8 | 0:7.61.1-34.el8_10.13 | [ELSA-2026-57462](https://patchblox.com/security/data/fix/linux/elsa-2026-57462.md) | Aug 20, 2026 |
| Linux | libcurl ol 9 | 0:7.76.1-40.el9_8.5 | [ELSA-2026-55439](https://patchblox.com/security/data/fix/linux/elsa-2026-55439.md) | Aug 17, 2026 |
| Linux | libcurl-debuginfo amzn 2023 | 8.21.0-5.amzn2023.0.1 | [ALAS2023-2026-2132](https://patchblox.com/security/data/fix/linux/alas2023-2026-2132.md) | Sep 14, 2026 |
| Linux | libcurl-devel RHEL 8 | 0:7.61.1-34.el8_10.13 | [RHSA-2026:57462](https://patchblox.com/security/data/fix/linux/rhsa-2026-57462.md) | Aug 20, 2026 |
| Linux | libcurl-devel RHEL 9 | 0:7.76.1-40.el9_8.5 | [RHSA-2026:55439](https://patchblox.com/security/data/fix/linux/rhsa-2026-55439.md) | Aug 19, 2026 |
| Linux | libcurl-devel almalinux 8 | 7.61.1-34.el8_10.13 | [ALSA-2026:57462](https://patchblox.com/security/data/fix/linux/alsa-2026-57462.md) | Aug 20, 2026 |
| Linux | libcurl-devel almalinux 9 | 7.76.1-40.el9_8.5 | [ALSA-2026:55439](https://patchblox.com/security/data/fix/linux/alsa-2026-55439.md) | Aug 17, 2026 |
| Linux | libcurl-devel amzn 2023 | 8.21.0-5.amzn2023.0.1 | [ALAS2023-2026-2132](https://patchblox.com/security/data/fix/linux/alas2023-2026-2132.md) | Sep 14, 2026 |
| Linux | libcurl-devel ol 10 | 0:8.12.1-4.el10_2.4 | [ELSA-2026-55450](https://patchblox.com/security/data/fix/linux/elsa-2026-55450.md) | Aug 17, 2026 |
| Linux | libcurl-devel ol 8 | 0:7.61.1-34.el8_10.13 | [ELSA-2026-57462](https://patchblox.com/security/data/fix/linux/elsa-2026-57462.md) | Aug 20, 2026 |
| Linux | libcurl-devel ol 9 | 0:7.76.1-40.el9_8.5 | [ELSA-2026-55439](https://patchblox.com/security/data/fix/linux/elsa-2026-55439.md) | Aug 17, 2026 |
| Linux | libcurl-minimal RHEL 8 | 0:7.61.1-34.el8_10.13 | [RHSA-2026:57462](https://patchblox.com/security/data/fix/linux/rhsa-2026-57462.md) | Aug 20, 2026 |
| Linux | libcurl-minimal RHEL 9 | 0:7.76.1-40.el9_8.5 | [RHSA-2026:55439](https://patchblox.com/security/data/fix/linux/rhsa-2026-55439.md) | Aug 19, 2026 |
| Linux | libcurl-minimal almalinux 8 | 7.61.1-34.el8_10.13 | [ALSA-2026:57462](https://patchblox.com/security/data/fix/linux/alsa-2026-57462.md) | Aug 20, 2026 |
| Linux | libcurl-minimal almalinux 9 | 7.76.1-40.el9_8.5 | [ALSA-2026:55439](https://patchblox.com/security/data/fix/linux/alsa-2026-55439.md) | Aug 17, 2026 |
| Linux | libcurl-minimal amzn 2023 | 8.21.0-5.amzn2023.0.1 | [ALAS2023-2026-2132](https://patchblox.com/security/data/fix/linux/alas2023-2026-2132.md) | Sep 14, 2026 |
| Linux | libcurl-minimal ol 10 | 0:8.12.1-4.el10_2.4 | [ELSA-2026-55450](https://patchblox.com/security/data/fix/linux/elsa-2026-55450.md) | Aug 17, 2026 |
| Linux | libcurl-minimal ol 8 | 0:7.61.1-34.el8_10.13 | [ELSA-2026-57462](https://patchblox.com/security/data/fix/linux/elsa-2026-57462.md) | Aug 20, 2026 |
| Linux | libcurl-minimal ol 9 | 0:7.76.1-40.el9_8.5 | [ELSA-2026-55439](https://patchblox.com/security/data/fix/linux/elsa-2026-55439.md) | Aug 17, 2026 |
| Linux | libcurl-minimal-debuginfo amzn 2023 | 8.21.0-5.amzn2023.0.1 | [ALAS2023-2026-2132](https://patchblox.com/security/data/fix/linux/alas2023-2026-2132.md) | Sep 14, 2026 |
| Linux | libcurl3-gnutls Ubuntu 18.04.6 LTS (bionic) | 7.58.0-2ubuntu3.24+esm9 | [libcurl3-gnutls 7.58.0-2ubuntu3.24+esm9](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libcurl3-gnutls-7.58.0-2ubuntu3.24-esm9.md) | Jul 3, 2026 |
| Linux | libcurl3-gnutls Ubuntu 20.04 LTS (focal) | 7.68.0-1ubuntu2.25+esm4 | [libcurl3-gnutls 7.68.0-1ubuntu2.25+esm4](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libcurl3-gnutls-7.68.0-1ubuntu2.25-esm4.md) | Jul 3, 2026 |
| Linux | libcurl3-gnutls Ubuntu 22.04.1 LTS (jammy) | 7.81.0-1ubuntu1.25 | [libcurl3-gnutls 7.81.0-1ubuntu1.25](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libcurl3-gnutls-7.81.0-1ubuntu1.25.md) | Jul 3, 2026 |
| Linux | libcurl3-nss Ubuntu 18.04.6 LTS (bionic) | 7.58.0-2ubuntu3.24+esm9 | [libcurl3-nss 7.58.0-2ubuntu3.24+esm9](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libcurl3-nss-7.58.0-2ubuntu3.24-esm9.md) | Jul 3, 2026 |
| Linux | libcurl3-nss Ubuntu 20.04 LTS (focal) | 7.68.0-1ubuntu2.25+esm4 | [libcurl3-nss 7.68.0-1ubuntu2.25+esm4](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libcurl3-nss-7.68.0-1ubuntu2.25-esm4.md) | Jul 3, 2026 |
| Linux | libcurl3-nss Ubuntu 22.04.1 LTS (jammy) | 7.81.0-1ubuntu1.25 | [libcurl3-nss 7.81.0-1ubuntu1.25](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libcurl3-nss-7.81.0-1ubuntu1.25.md) | Jul 3, 2026 |
| Linux | libcurl3t64-gnutls Ubuntu 24.04.5 LTS (noble) | 8.5.0-2ubuntu10.10 | [libcurl3t64-gnutls 8.5.0-2ubuntu10.10](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libcurl3t64-gnutls-8.5.0-2ubuntu10.10.md) | Jul 3, 2026 |
| Linux | libcurl3t64-gnutls Ubuntu 25.10 (questing) | 8.14.1-2ubuntu1.4 | [libcurl3t64-gnutls 8.14.1-2ubuntu1.4](https://patchblox.com/security/data/fix/linux/ubuntu-questing-libcurl3t64-gnutls-8.14.1-2ubuntu1.4.md) | Jul 3, 2026 |
| Linux | libcurl3t64-gnutls Ubuntu 26.04.1 LTS (resolute) | 8.18.0-1ubuntu2.2 | [libcurl3t64-gnutls 8.18.0-1ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libcurl3t64-gnutls-8.18.0-1ubuntu2.2.md) | Jun 26, 2026 |
| Linux | libcurl4 Ubuntu 18.04.6 LTS (bionic) | 7.58.0-2ubuntu3.24+esm9 | [libcurl4 7.58.0-2ubuntu3.24+esm9](https://patchblox.com/security/data/fix/linux/ubuntu-bionic-libcurl4-7.58.0-2ubuntu3.24-esm9.md) | Jul 3, 2026 |
| Linux | libcurl4 Ubuntu 20.04 LTS (focal) | 7.68.0-1ubuntu2.25+esm4 | [libcurl4 7.68.0-1ubuntu2.25+esm4](https://patchblox.com/security/data/fix/linux/ubuntu-focal-libcurl4-7.68.0-1ubuntu2.25-esm4.md) | Jul 3, 2026 |
| Linux | libcurl4 Ubuntu 22.04.1 LTS (jammy) | 7.81.0-1ubuntu1.25 | [libcurl4 7.81.0-1ubuntu1.25](https://patchblox.com/security/data/fix/linux/ubuntu-jammy-libcurl4-7.81.0-1ubuntu1.25.md) | Jul 3, 2026 |
| Linux | libcurl4t64 Ubuntu 24.04.5 LTS (noble) | 8.5.0-2ubuntu10.10 | [libcurl4t64 8.5.0-2ubuntu10.10](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libcurl4t64-8.5.0-2ubuntu10.10.md) | Jul 3, 2026 |
| Linux | libcurl4t64 Ubuntu 25.10 (questing) | 8.14.1-2ubuntu1.4 | [libcurl4t64 8.14.1-2ubuntu1.4](https://patchblox.com/security/data/fix/linux/ubuntu-questing-libcurl4t64-8.14.1-2ubuntu1.4.md) | Jul 3, 2026 |
| Linux | libcurl4t64 Ubuntu 26.04.1 LTS (resolute) | 8.18.0-1ubuntu2.2 | [libcurl4t64 8.18.0-1ubuntu2.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libcurl4t64-8.18.0-1ubuntu2.2.md) | Jun 26, 2026 |

---

Data as of 2026-11-08T00:53:09Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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