VulnerabilityPublished 18 Sep 2026Updated 17 Oct 2026

CVE-2026-93579: Netty's HTTP/2 stack · CWE-1035

Affects nettySource GCVE Database

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Authoritative record:CVE-2026-93579· Medium 6.5

Not known to be exploited · CVSS 6.5 Medium.

Data as of 8 Nov 2026, 23:24 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none

CVSS scores by source
CNA (redhat)	CVSS 3.1	6.5

EPSS: 1.0% chance of exploitation in 30 days – higher than 65% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 8 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Ubuntu 26.10netty`pkg:deb/ubuntu/netty?arch=source&distro=stonking`Other threats	Affected =1:4.1.48-16 =1:4.1.48-16ubuntu1	Fixed in–
Ubuntu Pro 26.04 LTSnetty`pkg:deb/ubuntu/netty?arch=source&distro=esm-apps/resolute`Other threats	Affected 1:4.1.48-10 – 1:4.1.48-16ubuntu0.1~esm2 7 affected builds	Fixed in–
Ubuntu Pro 24.04 LTSnetty`pkg:deb/ubuntu/netty?arch=source&distro=esm-apps/noble`Other threats	Affected 1:4.1.48-7 – 1:4.1.48-9ubuntu0.2+esm2 11 affected builds	Fixed in–
Ubuntu Pro 22.04 LTSnetty`pkg:deb/ubuntu/netty?arch=source&distro=esm-apps/jammy`Other threats	Affected 1:4.1.48-4 – 1:4.1.48-4+deb11u2ubuntu0.2+esm1 10 affected builds	Fixed in–
Ubuntu Pro 20.04 LTSnetty`pkg:deb/ubuntu/netty?arch=source&distro=esm-apps/focal`Other threats	Affected 1:4.1.33-1 – 1:4.1.45-1ubuntu0.1~esm7 10 affected builds	Fixed in–
Ubuntu Pro 18.04 LTSnetty`pkg:deb/ubuntu/netty?arch=source&distro=esm-apps/bionic`Other threats	Affected 1:4.1.7-4 – 1:4.1.7-4ubuntu0.1~esm1 10 affected builds	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Red Hat has released an official security update for the Red Hat build of Quarkus in version 3.33.3.SP2 that addresses this vulnerability. Users should apply this update to remediate the issue. Prior to applying this update, ensure all previously released errata relevant to your system have been applied. No other specific mitigations are indicated by the vendor advisory.

Description

CVE-2026-93579 is a medium severity vulnerability in the Red Hat build of Quarkus 3.27.5.SP2 caused by insufficient validation of HTTP/2 header field values in Netty's HTTP/2 stack. This flaw allows remote attackers to inject prohibited characters such as NUL, Line Feed, and Carriage Return into HTTP/2 headers. When these headers are translated from HTTP/2 to HTTP/1.1, the vulnerability can be exploited for HTTP request smuggling, header injection, or response splitting, potentially leading to unauthorized access or data manipulation. Red Hat has issued an important security advisory with updates available in Quarkus 3.33.3.SP2 that address this and other vulnerabilities.

Impact

Successful exploitation of this vulnerability could allow remote attackers to perform HTTP request smuggling, header injection, or response splitting attacks. This may result in unauthorized access to resources, manipulation of data, or bypassing of security mechanisms. The CVSS v3.1 base score is 6.5 (medium severity), indicating a significant but not critical impact. There are no known exploits in the wild at this time.

Summary

The vulnerability CVE-2026-93579 exists in Netty's HTTP/2 codec used by the Red Hat build of Quarkus. It stems from insufficient validation of HTTP/2 header field values, allowing injection of control characters (NUL, LF, CR). This can be exploited when HTTP/2 headers are translated to HTTP/1.1, enabling attacks such as request smuggling, header injection, or response splitting. These attacks may lead to unauthorized access, data manipulation, or bypassing security controls. The issue affects multiple specific versions of Red Hat build of Quarkus as listed. Red Hat has released a security update in Quarkus 3.33.3.SP2 addressing this vulnerability among others.

CWE-1035OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities (opens in a new tab)
CategoryOWASP Top 10 A03:2025: Software Supply Chain Failures (opens in a new tab)
Weaknesses in this category are related to the A9 category in the OWASP Top Ten 2017.
MITRE does not allow mapping vulnerabilities to this entry; it groups weaknesses rather than naming one.
OWASP Cheat Sheets
OWASP Cheat Sheet Series: Dependency Graph SBOM (opens in a new tab)
OWASP Cheat Sheet Series: Vulnerable Dependency Management (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 12 Oct 2026, 22:55 UTC

WeaknessesCWE-1035

Technical details

References

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