CVE-2026-6733
ADVISORY - githubSummary
Impact
Undici's HTTP/1.1 client is vulnerable to response queue poisoning on reused keep-alive sockets. An attacker-controlled upstream server can inject an unsolicited HTTP/1.1 response onto an idle socket after a request completes. When the client dispatches the next request on that socket, it associates the injected response with the new request, causing responses to be delivered to the wrong requests.
This requires an attacker-controlled or compromised upstream HTTP/1.1 server and keep-alive connection reuse.
Patches
Upgrade to undici v6.27.0, v7.28.0 or v8.5.0.
Workarounds
Disable keep-alive connection reuse by setting keepAliveTimeout: 0 on the Client or Pool.
Common Weakness Enumeration (CWE)
Time-of-check Time-of-use (TOCTOU) Race Condition
Improper Verification of Source of a Communication Channel
GitHub
2.2
CVSS SCORE
3.7low| Package | Type | OS Name | OS Version | Affected Ranges | Fix Versions |
|---|---|---|---|---|---|
| undici | npm | - | - | <6.27.0 | 6.27.0 |
| undici | npm | - | - | >=7.0.0,<7.28.0 | 7.28.0 |
| undici | npm | - | - | >=8.0.0,<8.5.0 | 8.5.0 |
CVSS:3 Severity and metrics
The CVSS metrics represent different qualitative aspects of a vulnerability that impact the overall score, as defined by the CVSS Specification.
The vulnerable component is bound to the network stack, but the attack is limited at the protocol level to a logically adjacent topology. This can mean an attack must be launched from the same shared physical (e.g., Bluetooth or IEEE 802.11) or logical (e.g., local IP subnet) network, or from within a secure or otherwise limited administrative domain (e.g., MPLS, secure VPN to an administrative network zone). One example of an Adjacent attack would be an ARP (IPv4) or neighbor discovery (IPv6) flood leading to a denial of service on the local LAN segment (e.g., CVE-2013-6014).
A successful attack depends on conditions beyond the attacker's control, requiring investing a measurable amount of effort in research, preparation, or execution against the vulnerable component before a successful attack.
The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
The vulnerable system can be exploited without interaction from any user.
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.
There is no loss of confidentiality.
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.
There is no impact to availability within the impacted component.
Debian
-
Ubuntu
-
CVSS SCORE
N/AmediumRed Hat
2.2
CVSS SCORE
3.7lowChainguard
CGA-j3pq-hjm5-hx8h
-
minimos
MINI-m77v-6x22-pq5p
-
minimos
MINI-pjw6-9ff5-qp97
-
minimos
MINI-v647-4rr9-344c
-