CVE-2026-34183

7.5 HIGH 1% exploit odds Fix listed Denial of service Library

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in. High risk of service disruption.
Exploit odds: 1.0% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-06-09 17:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-07-23 08:10 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 1.0% in the next 30 days (EPSS).
Severity: 7.5 HIGH (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-06-09 17:17 UTC
Last modified: 2026-07-23 08:10 UTC
Exploit probability: 1.0% · EPSS, next 30 days
Weakness: CWE-1325
Record status: Analyzed

Affected

OpenSSL < 3.4.6
OpenSSL < 3.5.7
OpenSSL < 3.6.3
OpenSSL 4.0.0

Attack profile CVSS 3.1 · 7.5

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Is it in your code?

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Fix and advisories

References

NVD record · CVE.org record