Review reviewHigh

CVE-2026-34183

OpenSSL OpenSSL, openssl

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 remot...

CVSS: 7.5
EPSS: 1.05%
CISA KEV: Not listed
Published: 2026.06.10

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability1.05%

Technical severityCVSS 7.5

Vulnerability overview

Affected product and versions

Product: OpenSSL OpenSSL, openssl
Affected versions: >= 4.0.0 < 4.0.1, >= 3.6.0 < 3.6.3, >= 3.5.0 < 3.5.7, >= 3.4.0 < 3.4.6, 4.0.0
Fixed versions: 3.4.6, 3.5.7, 3.6.3

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that OpenSSL OpenSSL, openssl and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE: CWE-1325