8.7

CVE-2026-33871: Netty HTTP/2 CONTINUATION Frame Flood DoS via Zero-Byte Frame Bypass

Modified
AliasesUBUNTU-CVE-2026-33871DEBIAN-CVE-2026-33871CGA-23q3-cwp3-6vch
Published 27-03-2026Last modified 15-09-2026

Vulnerability summary

CVE-2026-33871 is a high (CVSS 8.7) vulnerability in netty. EPSS estimates a 1.15% chance of exploitation in the next 30 days, higher than 66.7% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 8.7 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 1% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
8.7/10
010
High · v4.0 (CVE.org)
EPSS score
1.15%
0%100%
Low · -0.06 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 4 · Related 3
OPENSUSE-SU-2026:10463-1RHSA-2026:18054RHSA-2026:18055SUSE-SU-2026:1353-1CGA-PFVR-2RWF-CG7P

Timeline

  1. 27-03-2026
    PublishedVulnerability first disclosed.
  2. 15-09-2026
    Last modifiedVulnerability information updated.

Description

Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.132.Final and 4.2.10.Final, a remote user can trigger a Denial of Service (DoS) against a Netty HTTP/2 server by sending a flood of `CONTINUATION` frames. The server's lack of a limit on the number of `CONTINUATION` frames, combined with a bypass of existing size-based mitigations using zero-byte frames, allows an user to cause excessive CPU consumption with minimal bandwidth, rendering the server unresponsive. Versions 4.1.132.Final and 4.2.10.Final fix the issue.

CVSS metrics

10 scores · 7 sources · 2 versions

EPSS trend

Probability

1.15%

Chance of exploitation in the next 30 days

Percentile

67%

Versus all other CVEs

30-day change

Decrease -0.06 pp

From 1.20% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard196 products
  • akhq< 0.27.0-r0
  • apache-camel-karavan-devmode< 4.14.2-r6 | < 4.14.2-r7
  • apache-hop< 2.17.0-r6
  • apache-hop-fips< 2.17.0-r6
  • apache-pulsar-4.0< 4.0.9-r10
Wolfi4 products
  • akhq< 0.27.0-r0
  • apache-pulsar-4.1< 4.1.3-r15
  • apache-pulsar-4.2< 4.2.1-r0
  • apicurio-registry< 3.2.0-r3

2 vendors · 200 products · Showing 200 of 263

References

27 links
Show all 27 references