# CVE-2026-9547: curl: When a libcurl-based application performs transfers via `SCP://` or `SFTP://` and utilizes the `CURLOPT_SSH_KEYFUNCTI...

CVE-2026-9547 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-2026-9547
- Priority: High
- CVSS: 8.1 (high)
- EPSS: 0.0036
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 24, 2026

## Description

When a libcurl-based application performs transfers via `SCP://` or `SFTP://` and utilizes the `CURLOPT_SSH_KEYFUNCTION` callback, it may silently accept an untrusted server. This vulnerability occurs when a server presents a host key type that does not match the specific key type already recorded for that host in the `known_hosts` file. Instead of rejecting the mismatch, the callback mechanism fails to properly enforce the restriction, allowing the connection to succeed without warning and risking a potential man-in-the-middle attack.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | curl Debian 14 | 8.21.0~rc2-1 | [DEBIAN-CVE-2026-9547](https://patchblox.com/security/data/fix/linux/debian-cve-2026-9547.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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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 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

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.