# CVE-2026-34183: Unbounded Memory Growth in the QUIC PATH_CHALLENGE Handler

CVE-2026-34183 is fixed in 14 products on 1 platform, first by RHSA-2026:71542, released March 12, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-34183
- Priority: High
- CVSS: 9.1 (Moderate)
- EPSS: 0.0105
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 8, 2026
- Weakness: Improperly Controlled Sequential Memory Allocation
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-34183

## Description

Issue summary: Remote peer may exhaust heap memory of the QUIC server or client by flooding it with packets containing PATH_CHALLENGE frames. Impact summary: A malicious remote peer can cause an unbounded memory allocation which can lead to an abnormal termination of the application acting as a QUIC client or server and a Denial of Service. A remote peer may exhaust heap memory by flooding the local QUIC stack with PATH_CHALLENGE frames. The local QUIC stack allocates a PATH_RESPONSE frame for every PATH_CHALLENGE it receives. The allocated PATH_RESPONSE frame gets freed only when the remote peer acknowledges reception of the PATH_RESPONSE frame which will not be done by a malicious peer. The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this issue. The QUIC stack is outside of OpenSSL FIPS module boundary.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libssl3t64 Ubuntu 25.10 (questing) | 3.5.3-1ubuntu3.4 | [libssl3t64 3.5.3-1ubuntu3.4](https://patchblox.com/security/data/fix/linux/ubuntu-questing-libssl3t64-3.5.3-1ubuntu3.4.md) | Jun 24, 2026 |
| Linux | libssl3t64 Ubuntu 26.04.1 LTS (resolute) | 3.5.5-1ubuntu3.2 | [libssl3t64 3.5.5-1ubuntu3.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libssl3t64-3.5.5-1ubuntu3.2.md) | Jun 8, 2026 |
| Linux | openssl Debian 13.5 (trixie) | 3.5.6-1~deb13u2 | [DEBIAN-CVE-2026-34183](https://patchblox.com/security/data/fix/linux/debian-cve-2026-34183.md) | Jun 24, 2026 |
| Linux | openssl Debian 14 | 3.6.3-1 | [DEBIAN-CVE-2026-34183](https://patchblox.com/security/data/fix/linux/debian-cve-2026-34183.md) | Jun 24, 2026 |
| Linux | openssl RHEL 10 | 3.2.2-16.el10_0.7 | [RHSA-2026:71542](https://patchblox.com/security/data/fix/linux/rhsa-2026-71542.md) | Mar 12, 2026 |
| Linux | openssl RHEL 9 | 1:3.5.5-4.el9_8 | [RHSA-2026:25239](https://patchblox.com/security/data/fix/linux/rhsa-2026-25239.md) | Jun 24, 2026 |
| Linux | openssl Ubuntu 25.10 (questing) | 3.5.3-1ubuntu3.4 | [openssl 3.5.3-1ubuntu3.4](https://patchblox.com/security/data/fix/linux/ubuntu-questing-openssl-3.5.3-1ubuntu3.4.md) | Jun 24, 2026 |
| Linux | openssl Ubuntu 26.04.1 LTS (resolute) | 3.5.5-1ubuntu3.2 | [openssl 3.5.5-1ubuntu3.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-openssl-3.5.5-1ubuntu3.2.md) | Jun 8, 2026 |
| Linux | openssl almalinux 10 | 1:3.5.5-4.el10_2.alma.1 | [ALSA-2026:25237](https://patchblox.com/security/data/fix/linux/alsa-2026-25237.md) | Jun 11, 2026 |
| Linux | openssl almalinux 9 | 1:3.5.5-4.el9_8 | [ALSA-2026:25239](https://patchblox.com/security/data/fix/linux/alsa-2026-25239.md) | Jun 11, 2026 |
| Linux | openssl amzn 2023 | 1:3.5.5-1.amzn2023.0.5 | [ALAS2023-2026-1853](https://patchblox.com/security/data/fix/linux/alas2023-2026-1853.md) | Jun 22, 2026 |
| Linux | openssl ol 10 | 1:3.5.5-5.0.1.el10_2 | [ELSA-2026-25237](https://patchblox.com/security/data/fix/linux/elsa-2026-25237.md) | Jul 28, 2026 |
| Linux | openssl ol 9 | 1:3.5.5-4.0.1.el9_8 | [ELSA-2026-25239](https://patchblox.com/security/data/fix/linux/elsa-2026-25239.md) | Jun 23, 2026 |
| Linux | openssl rocky 10 | 1:3.5.5-4.el10_2 | [RLSA-2026:25237](https://patchblox.com/security/data/fix/linux/rlsa-2026-25237.md) | Jun 13, 2026 |
| Linux | openssl rocky 9 | 1:3.5.5-4.el9_8 | [RLSA-2026:25239](https://patchblox.com/security/data/fix/linux/rlsa-2026-25239.md) | Jun 13, 2026 |
| Linux | openssl-3 opensuse-leap 16.0 | 3.5.0-160000.8.1 | [OPENSUSE-SU-2026:21005-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21005-1.md) | Jun 22, 2026 |
| Linux | openssl-3 sles 15.7 | 3.2.3-150700.5.36.1 | [SUSE-SU-2026:2648-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-2648-1.md) | Jun 26, 2026 |
| Linux | openssl-3 sles 16.0 | 3.5.0-160000.8.1 | [SUSE-SU-2026:22315-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-22315-1.md) | Jun 22, 2026 |
| Linux | openssl-debuginfo amzn 2023 | 1:3.5.5-1.amzn2023.0.5 | [ALAS2023-2026-1853](https://patchblox.com/security/data/fix/linux/alas2023-2026-1853.md) | Jun 22, 2026 |
| Linux | openssl-debugsource amzn 2023 | 1:3.5.5-1.amzn2023.0.5 | [ALAS2023-2026-1853](https://patchblox.com/security/data/fix/linux/alas2023-2026-1853.md) | Jun 22, 2026 |
| Linux | openssl-devel RHEL 9 | 1:3.5.5-4.el9_8 | [RHSA-2026:25239](https://patchblox.com/security/data/fix/linux/rhsa-2026-25239.md) | Jun 24, 2026 |
| Linux | openssl-devel almalinux 10 | 1:3.5.5-4.el10_2.alma.1 | [ALSA-2026:25237](https://patchblox.com/security/data/fix/linux/alsa-2026-25237.md) | Jun 11, 2026 |
| Linux | openssl-devel almalinux 9 | 1:3.5.5-4.el9_8 | [ALSA-2026:25239](https://patchblox.com/security/data/fix/linux/alsa-2026-25239.md) | Jun 11, 2026 |
| Linux | openssl-devel amzn 2023 | 1:3.5.5-1.amzn2023.0.5 | [ALAS2023-2026-1853](https://patchblox.com/security/data/fix/linux/alas2023-2026-1853.md) | Jun 22, 2026 |
| Linux | openssl-devel ol 10 | 1:3.5.5-5.0.1.el10_2 | [ELSA-2026-25237](https://patchblox.com/security/data/fix/linux/elsa-2026-25237.md) | Jul 28, 2026 |
| Linux | openssl-devel ol 9 | 1:3.5.5-4.0.1.el9_8 | [ELSA-2026-25239](https://patchblox.com/security/data/fix/linux/elsa-2026-25239.md) | Jun 23, 2026 |
| Linux | openssl-fips-provider-latest amzn 2023 | 1:3.5.5-1.amzn2023.0.5 | [ALAS2023-2026-1853](https://patchblox.com/security/data/fix/linux/alas2023-2026-1853.md) | Jun 22, 2026 |
| Linux | openssl-fips-provider-latest-debuginfo amzn 2023 | 1:3.5.5-1.amzn2023.0.5 | [ALAS2023-2026-1853](https://patchblox.com/security/data/fix/linux/alas2023-2026-1853.md) | Jun 22, 2026 |
| Linux | openssl-libs RHEL 9 | 1:3.5.5-4.el9_8 | [RHSA-2026:25239](https://patchblox.com/security/data/fix/linux/rhsa-2026-25239.md) | Jun 24, 2026 |
| Linux | openssl-libs almalinux 10 | 1:3.5.5-4.el10_2.alma.1 | [ALSA-2026:25237](https://patchblox.com/security/data/fix/linux/alsa-2026-25237.md) | Jun 11, 2026 |
| Linux | openssl-libs almalinux 9 | 1:3.5.5-4.el9_8 | [ALSA-2026:25239](https://patchblox.com/security/data/fix/linux/alsa-2026-25239.md) | Jun 11, 2026 |
| Linux | openssl-libs amzn 2023 | 1:3.5.5-1.amzn2023.0.5 | [ALAS2023-2026-1853](https://patchblox.com/security/data/fix/linux/alas2023-2026-1853.md) | Jun 22, 2026 |
| Linux | openssl-libs ol 10 | 1:3.5.5-5.0.1.el10_2 | [ELSA-2026-25237](https://patchblox.com/security/data/fix/linux/elsa-2026-25237.md) | Jul 28, 2026 |
| Linux | openssl-libs ol 9 | 1:3.5.5-4.0.1.el9_8 | [ELSA-2026-25239](https://patchblox.com/security/data/fix/linux/elsa-2026-25239.md) | Jun 23, 2026 |
| Linux | openssl-libs-debuginfo amzn 2023 | 1:3.5.5-1.amzn2023.0.5 | [ALAS2023-2026-1853](https://patchblox.com/security/data/fix/linux/alas2023-2026-1853.md) | Jun 22, 2026 |
| Linux | openssl-perl RHEL 9 | 1:3.5.5-4.el9_8 | [RHSA-2026:25239](https://patchblox.com/security/data/fix/linux/rhsa-2026-25239.md) | Jun 24, 2026 |
| Linux | openssl-perl almalinux 10 | 1:3.5.5-4.el10_2.alma.1 | [ALSA-2026:25237](https://patchblox.com/security/data/fix/linux/alsa-2026-25237.md) | Jun 11, 2026 |
| Linux | openssl-perl almalinux 9 | 1:3.5.5-4.el9_8 | [ALSA-2026:25239](https://patchblox.com/security/data/fix/linux/alsa-2026-25239.md) | Jun 11, 2026 |
| Linux | openssl-perl amzn 2023 | 1:3.5.5-1.amzn2023.0.5 | [ALAS2023-2026-1853](https://patchblox.com/security/data/fix/linux/alas2023-2026-1853.md) | Jun 22, 2026 |
| Linux | openssl-perl ol 10 | 1:3.5.5-5.0.1.el10_2 | [ELSA-2026-25237](https://patchblox.com/security/data/fix/linux/elsa-2026-25237.md) | Jul 28, 2026 |
| Linux | openssl-perl ol 9 | 1:3.5.5-4.0.1.el9_8 | [ELSA-2026-25239](https://patchblox.com/security/data/fix/linux/elsa-2026-25239.md) | Jun 23, 2026 |
| Linux | openssl-provider-legacy Ubuntu 25.10 (questing) | 3.5.3-1ubuntu3.4 | [openssl-provider-legacy 3.5.3-1ubuntu3.4](https://patchblox.com/security/data/fix/linux/ubuntu-questing-openssl-provider-legacy-3.5.3-1ubuntu3.4.md) | Jun 24, 2026 |
| Linux | openssl-provider-legacy Ubuntu 26.04.1 LTS (resolute) | 3.5.5-1ubuntu3.2 | [openssl-provider-legacy 3.5.5-1ubuntu3.2](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-openssl-provider-legacy-3.5.5-1ubuntu3.2.md) | Jun 8, 2026 |
| Linux | openssl-snapsafe-libs amzn 2023 | 1:3.5.5-1.amzn2023.0.5 | [ALAS2023-2026-1853](https://patchblox.com/security/data/fix/linux/alas2023-2026-1853.md) | Jun 22, 2026 |
| Linux | openssl-snapsafe-libs-debuginfo amzn 2023 | 1:3.5.5-1.amzn2023.0.5 | [ALAS2023-2026-1853](https://patchblox.com/security/data/fix/linux/alas2023-2026-1853.md) | Jun 22, 2026 |

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