7.5

CVE-2024-30255: envoyproxy envoy

CVSS: 7.5v3.1HighModified
Published 04-04-2024Last modified 04-11-2025
Open JSON

Vulnerability summary

CVE-2024-30255 is a high (CVSS 7.5) vulnerability in envoyproxy envoy. EPSS estimates a 87.81% chance of exploitation in the next 30 days, higher than 99.7% of scored vulnerabilities.

Overall risk
48/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (NVD)
EPSS score
87.81%
0%100%
Critical · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 04-04-2024
    PublishedVulnerability first disclosed.
  2. 04-11-2025
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

87.81%

Chance of exploitation in the next 30 days

Percentile

100%

Versus all other CVEs

30-day change

0.00 pp

From 87.81% on 20-09-2026

20-09-202620-10-2026
EPSS score
87.81%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Envoyproxy1 product
  • envoy< 1.26.8 | ≥ 1.27.0, < 1.27.4 | ≥ 1.28.0, < 1.28.2 | ≥ 1.29.0, < 1.29.3

1 vendor · 1 product

References

4 links