Envoy is a cloud-native, open source edge and service proxy. The HTTP/2 protocol stack in Envoy versions prior to 1.29.3, 1.28.2, 1.27.4, and 1.26.8 are vulnerable to CPU exhaustion due to flood of CONTINUATION frames. Envoy's HTTP/2 codec allows the client to send an unlimited number of CONTINUATION frames even after exceeding Envoy's header map limits. This allows an attacker to send a sequence of CONTINUATION frames without the END_HEADERS bit set causing CPU utilization, consuming approximately 1 core per 300Mbit/s of traffic and culminating in denial of service through CPU exhaustion. Users should upgrade to version 1.29.3, 1.28.2, 1.27.4, or 1.26.8 to mitigate the effects of the CONTINUATION flood. As a workaround, disable HTTP/2 protocol for downstream connections.
This vulnerability affects an unusually large number of packages. The highest-confidence fixes are shown above; the full list is longer. Check the referenced advisories for complete coverage.
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Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityLow
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Exploit Intelligence
87.81%probability of exploitation in 30 days
100thpercentile
Very high risk: more likely to be exploited than 100% of all known CVEs.
Published advisories record a fix for 28 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.
Is CVE-2024-30255 being actively exploited?
Not that we know of. CVE-2024-30255 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 87.8% is the estimated probability that it will be exploited in the next 30 days. That is higher than 100% of all scored CVEs.
How severe is CVE-2024-30255?
CVE-2024-30255 has a CVSS v3 base score of 5.3, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2024-30255 affect?
Published advisories record a fix for openshift-service (Rocky), openshift-service (Red Hat / RHEL), openshift-service-mesh/istio (Rocky), openshift-service-mesh/istio (Red Hat / RHEL), and 24 more. Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.
This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-11-04.
