CVE-2026-34183 Details
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.
View at NVD
Exploit prediction scoring system (EPSS) score for CVE-2026-34183
EPSS (Exploit Prediction Scoring System): EPSS predicts the likelihood that a vulnerability will be exploited in the wild. A higher percentage means a greater chance of an exploit occurring. The EPSS model produces a probability score between 0 and 1 (0 and 100%).
0.51 Probability of exploitation activity being observed over the next 30 days (40th percentile)
CVSS score for CVE-2026-34183
CVSS (Common Vulnerability Scoring System): An open framework owned and managed by FIRST.Org, Inc. that assigns a numerical score from 0 to 10 to software vulnerabilities to indicate their severity.
7.5 High
Products affected by CVE-2026-34183
OpenSSL 3.4.0
OpenSSL 3.4.1
OpenSSL 3.5.0
OpenSSL 3.6.2
OpenSSL 3.5.1
DVE Score by Bitsight AI
DVE scores complement traditional static scoring systems like CVSS with Bitsight AI powered real-time threat intelligence and underground cyber criminal activity so that security teams can reduce alert fatigue and focus on vulnerabilities most likely to be exploited.
Low
More on DVE scores

CVE-2026-34183 Global Footprint

Top 10 Identified Countries

Country Observations Percentage
US 14,869 34.88%
JP 3,903 9.16%
DE 3,479 8.16%
GB 1,952 4.58%
IE 1,902 4.46%
IN 1,821 4.27%
CA 1,329 3.12%
FR 1,287 3.02%
NL 979 2.30%
KR 748 1.75%

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CVE-2026-34183 Industry Footprint

Top 10 Identified Industries

*Service provider organizations (typically Technology and Telecommunications) are disproportionally represented in the results given their upstream ownership of end-user infrastructure. See our FAQs.

Industry* Observations Percentage
Technology 26,831 79.23%
Telecommunications 3,482 10.28%
Education 2,133 6.30%
Government/Politics 437 1.29%
Business Services 151 0.45%
Manufacturing 112 0.33%
Finance 104 0.31%
Healthcare/Wellness 90 0.27%
Utilities 73 0.22%
Energy/Resources 57 0.17%

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