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Fencer Vulns
high 7.5

CVE-2019-15226 in the critical feed json

Upon receiving each incoming request header data, Envoy will iterate over existing request headers to verify that the total size of the hea…

published 2019-10-09 7 y ago modified 2026-06-17 4 mo ago also EUVD-2019-6238

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
64.5%
EPSS 64.5% chance of exploitation in 30 days, percentile 99.2%
public exploits
0
none known

Summary

Upon receiving each incoming request header data, Envoy will iterate over existing request headers to verify that the total size of the headers stays below a maximum limit. The implementation in versions 1.10.0 through 1.11.1 for HTTP/1.x traffic and all versions of Envoy for HTTP/2 traffic had O(n^2) performance characteristics. A remote attacker may craft a request that stays below the maximum request header size but consists of many thousands of small headers to consume CPU and result in a denial-of-service attack.

Patch / fix

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2019-15226 updated cvss 7.5

envoy: crafted request allows remote attacker to cause denial of service

  • Red Hat OpenShift Service Mesh 1 envoy
    affected: no fix available

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

64.52% chance of exploitation in the next 30 days, higher than 99.2% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 7.8 AV:N/AC:L/Au:N/C:N/I:N/A:C

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.