← back
CVE-2026-34183

Unbounded Memory Growth in the QUIC PATH_CHALLENGE Handler

CVSS 7.5 HIGHEPSS 0.5%CWE-1325
In short

A attacker can send many QUIC PATH_CHALLENGE messages to a server or client, causing it to create response messages that are never cleaned up, eventually consuming all available memory and crashing the application.

Technical detail

Remote attacker floods the target with QUIC PATH_CHALLENGE frames, triggering creation of PATH_RESPONSE frames that accumulate in heap memory because the attacker never acknowledges them; unbounded memory allocation leads to resource exhaustion and denial of service. The vulnerability exists outside FIPS module boundaries in affected OpenSSL versions.

Summary generated and translated by AI from the official 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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
OpenSSL · OpenSSL

Want to know if your infrastructure is exposed to this?

Talk to TrueHacking →
References
https://github.com/openssl/openssl/commit/5b306efb0b3779dfdd0803b4afc9d08c91f11517https://github.com/openssl/openssl/commit/7d06955ebe0ecf8adfd4c1e92018586da47ef9achttps://github.com/openssl/openssl/commit/d2e9efbe4900a373227deb136e8665401404ffachttps://github.com/openssl/openssl/commit/fbaa83859c01ad64f497b757aaf51be7d05ed9ebhttps://openssl-library.org/news/secadv/20260609.txt