CVE-2026-97705VulnerabilityPublished 9 Nov 2026

Moleculer: Unauthenticated Denial of Service via negative length field in the TCP transporter packet parser

Affects moleculerSource GCVE Database

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Authoritative record:CVE-2026-97705· High 7.5

Not known to be exploited · CVSS 7.5 High : upgrade to 0.15.2 soon.

Data as of 9 Nov 2026, 23:24 UTC

CVSS 3.1 base score

7.5High

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

Thin evidence

One scorer or none

CVSS scores by source
CNA (GitHub_M)	CVSS 3.1	7.5

EPSS: 0.3% chance of exploitation in 30 days – higher than 28% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 0.15.2, 0.14.36

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

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

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: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 4 Nov 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 9 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

Upgrade moleculer to 0.15.2; moleculer to 0.14.36.

Affected software

Product	Affected	Fixed in
npmmoleculer	Affected >=0.15.0-beta1 <0.15.2	Fixed in 0.15.2
npmmoleculer	Affected <0.14.36	Fixed in 0.14.36

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AI-suggested

A patch is available in Moleculer versions 0.15.2 and 0.14.36 that fixes the vulnerability by validating the packet length field before processing. Users should upgrade to these versions or later to remediate the issue. No additional mitigations are required as the vulnerability is addressed by the official fix.

Description

Moleculer versions prior to 0.15.2 and 0.14.36 contain a vulnerability in the TCP transporter's packet parser that allows an unauthenticated remote attacker to cause a denial of service. By sending a crafted TCP packet with a negative length field, the parser enters an infinite synchronous loop, blocking the Node.js event loop and rendering the service unresponsive until restarted.

Impact

An unauthenticated remote attacker can send a single crafted TCP packet to any Moleculer node using the TCP transporter, causing the node's event loop to hang indefinitely. This blocks all services hosted in the Node.js process, resulting in a complete denial of service. The attack can be performed without any prior authentication or handshake and can be launched by any host able to reach the transporter's listening port, often discoverable via UDP broadcast on the same network segment. Neither CRC checks nor maxPacketSize settings mitigate this issue.

Summary

The TCP transporter's packet parser in Moleculer reads the packet length field using a signed 32-bit integer read. A crafted packet with the sign bit set causes the length to be negative. The parser attempts to slice the buffer by this negative length, but the slice clamps to zero, leaving the buffer unchanged. This results in an infinite loop in the parser's processing loop, blocking the Node.js event loop and causing a denial of service. The vulnerability is exploitable without authentication and before any protocol handshake. The issue affects the Parser._write function in src/transporters/tcp/parser.js. The fix, introduced in versions 0.15.2 and 0.14.36, validates that the length is at least the header size and rejects invalid lengths to prevent the infinite loop.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 9 Nov 2026, 23:20 UTC

WeaknessesCWE-835

Technical details

References

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