# CVE-2026-34183

## Summary

- **CVE ID:** CVE-2026-34183
- **Severity:** HIGH
- **CVSS Score:** 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
- **CWE:** CWE-1325
- **Published:** Jun 9, 2026
- **Last Modified:** Jun 10, 2026

## 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.

## Affected Products

- OpenSSL — OpenSSL (4.0.0)
- OpenSSL — OpenSSL (3.6.0)
- OpenSSL — OpenSSL (3.5.0)
- OpenSSL — OpenSSL (3.4.0)

## References

- [CNA](https://openssl-library.org/news/secadv/20260609.txt)
- [CNA](https://github.com/openssl/security/commit/fbaa83859c01ad64f497b757aaf51be7d05ed9eb)
- [CNA](https://github.com/openssl/security/commit/5b306efb0b3779dfdd0803b4afc9d08c91f11517)
- [CNA](https://github.com/openssl/security/commit/7d06955ebe0ecf8adfd4c1e92018586da47ef9ac)
- [CNA](https://github.com/openssl/security/commit/d2e9efbe4900a373227deb136e8665401404ffac)
- [CNA](https://github.com/openssl/openssl/commit/fbaa83859c01ad64f497b757aaf51be7d05ed9eb)
- [CNA](https://github.com/openssl/openssl/commit/5b306efb0b3779dfdd0803b4afc9d08c91f11517)
- [CNA](https://github.com/openssl/openssl/commit/7d06955ebe0ecf8adfd4c1e92018586da47ef9ac)
- [CNA](https://github.com/openssl/openssl/commit/d2e9efbe4900a373227deb136e8665401404ffac)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 1.05%
- **EPSS Percentile:** 62.2

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._