# CVE-2026-11586: curl: By default, curl automatically responds to WebSocket PING frames

CVE-2026-11586 is fixed in 12 products on 1 platform, first by curl 8.18.0-1ubuntu2.3, released June 24, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-11586
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0086
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 24, 2026

## Description

By default, curl automatically responds to WebSocket PING frames. Because curl lacks an upper bound on memory allocation for unacknowledged frames, a malicious server can exhaust all available memory by flooding curl with rapid, sequential PING messages.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | curl Debian 14 | 8.21.0~rc3-1 | [DEBIAN-CVE-2026-11586](https://patchblox.com/security/data/fix/linux/debian-cve-2026-11586.md) | Jul 24, 2026 |
| Linux | curl Ubuntu 26.04.1 LTS (resolute) | 8.18.0-1ubuntu2.3 | [curl 8.18.0-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-curl-8.18.0-1ubuntu2.3.md) | Jun 24, 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 sles 15.6 | 8.22.0-150600.4.58.1 | [SUSE-SU-2026:5069-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-5069-1.md) | Nov 7, 2026 |
| Linux | curl sles 15.7 | 8.22.0-150700.7.33.1 | [SUSE-SU-2026:5068-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-5068-1.md) | Nov 7, 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-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-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 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-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 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 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-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 | libcurl3t64-gnutls Ubuntu 26.04.1 LTS (resolute) | 8.18.0-1ubuntu2.3 | [libcurl3t64-gnutls 8.18.0-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libcurl3t64-gnutls-8.18.0-1ubuntu2.3.md) | Jun 24, 2026 |
| Linux | libcurl4t64 Ubuntu 26.04.1 LTS (resolute) | 8.18.0-1ubuntu2.3 | [libcurl4t64 8.18.0-1ubuntu2.3](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libcurl4t64-8.18.0-1ubuntu2.3.md) | Jun 24, 2026 |

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Data as of 2026-11-08T19:12:23Z 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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