Skip to content
statance
MenuClose
Log inStart for free ↗
medium · CVSS 6.5

CVE-2026-93579

Io.netty/netty-codec-http2: netty: http/2 header field values are not validated by default (cr/lf/nul passthrough)

Published 18 Sept 2026 · Source updated 6 Nov 2026 · Retrieved 2026-11-06 10:44 UTC

Monitor this CVE ↗Full CVE monitoring on Pro and Business

What happened?

A flaw was found in Netty's HTTP/2 stack. This vulnerability allows a remote attacker to inject prohibited characters, such as NUL, Line Feed, and Carriage Return, into HTTP/2 header field values due to insufficient validation. When these values cross an HTTP/2 to HTTP/1.1 translation boundary, they can be exploited for request smuggling, header injection, or response splitting. This could lead to unauthorized access, data manipulation, or other security bypasses.

Description supplied by CVE Program. Formatting is simplified; follow the original advisory for full details.

Affected software and versions

Source-provided software and version information
SoftwareVersion informationFixed version
netty-codec-http2Red HatDefault status: unaffectedSee vendor advisory
keycloak-rhel9-containerRed Hatunaffected: 26.4-29 to < *See vendor advisory
keycloak-rhel9-operator-bundle-containerRed Hatunaffected: 26.4.17-2 to < *See vendor advisory
keycloak-rhel9-operator-containerRed Hatunaffected: 26.4-30 to < *See vendor advisory
netty-codec-http2Red HatDefault status: unaffectedSee vendor advisory
netty-codec-http2Red HatDefault status: unaffectedSee vendor advisory
netty-codec-http2Red HatDefault status: unaffectedSee vendor advisory
netty-codec-http2Red HatDefault status: unaffectedSee vendor advisory
netty-codec-http2Red HatDefault status: unaffectedSee vendor advisory
netty-codec-http2Red HatDefault status: affectedSee vendor advisory
netty-codec-http2Red HatDefault status: affectedSee vendor advisory
netty-codec-http2Red HatDefault status: affectedSee vendor advisory
netty-codec-http2Red HatDefault status: affectedSee vendor advisory
netty-codec-http2Red HatDefault status: unknownSee vendor advisory
netty-codec-http2Red HatDefault status: unknownSee vendor advisory
netty-codec-http2Red HatDefault status: unaffectedSee vendor advisory
netty-codec-http2Red HatDefault status: affectedSee vendor advisory
netty-codec-http2Red HatDefault status: unknownSee vendor advisory

Version information comes from the source record and can include unaffected products and exceptions. Distribution packages may contain backported fixes: an older upstream version alone does not prove a server is affected.

Is it being exploited?

This CVE was not listed in the CISA catalogue at our last retrieval. This does not establish that exploitation is absent.

CISA data retrieved 2026-11-06 16:38 UTC. Check CISA ↗

How to respond

  1. Confirm the product, installed package version, and any configuration requirements in the vendor advisory.
  2. Follow the vendor’s remediation or workaround guidance in the references below. Structured fixed-version data is unavailable here; the publisher’s description may include a fix or workaround.
  3. Restart affected services if required, then verify the running version. Known exploitation may warrant investigation as well as patching.

Sources and remediation references

This public advisory does not determine whether a particular server is affected. Records are refreshed as sources change; verify urgent decisions against the original advisory.

← Browse the public CVE feed