VulnerabilityPublished 29 Sep 2026Updated 17 Oct 2026

CVE-2026-42772: Issue summary · The QUIC stream reassembly algorithm performance deteriorates progressively as packets are arriving out of order

Affects nodejsSource GCVE Database

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Not known to be exploited · CVSS 5.3 Medium · fixed in 3.1.8 : update nodejs when convenient.

Data as of 12 Nov 2026, 23:24 UTC

CVSS 3.1 base score

5.3Medium

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

EPSS: 0.4% chance of exploitation in 30 days – higher than 43% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 3.1.8, 3.5.5-1ubuntu3.7

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

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

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: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 29 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 13 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.

ghsa-5r49-x3jp-qp9h

What to do

Upgrade openssl/openssl to 3.1.8; the Ubuntu openssl package to 3.5.5-1ubuntu3.7.

Affected software

Product	Affected	Fixed in
GitHubopenssl/openssl`pkg:github/openssl/openssl`Other threats	Affected <3.1.8	Fixed in 3.1.8
Ubuntu Pro 22.04 LTSnodejs`pkg:deb/ubuntu/nodejs?arch=source&distro=esm-apps/jammy`Other threats	Affected 12.22.5~dfsg-5ubuntu1 – 12.22.9~dfsg-1ubuntu3.6+esm2 12 affected builds	Fixed in–
Ubuntu 26.04 LTSedk2`pkg:deb/ubuntu/edk2?arch=source&distro=resolute`Other threats	Affected 2025.02-8ubuntu3 – 2025.11-3ubuntu7.3 5 affected builds	Fixed in–
Ubuntu 26.04 LTSedk2-hwe`pkg:deb/ubuntu/edk2-hwe?arch=source&distro=resolute`Other threats	Affected =2025.11-3ubuntu6 =2025.11-3ubuntu8 =2025.11-3ubuntu8.2	Fixed in–
Ubuntu 26.04 LTSopenssl`pkg:deb/ubuntu/openssl?arch=source&distro=resolute`Other threats	Affected <3.5.5-1ubuntu3.7	Fixed in 3.5.5-1ubuntu3.7
Ubuntu 26.10edk2`pkg:deb/ubuntu/edk2?arch=source&distro=stonking`Other threats	Affected 2025.11-3ubuntu7 – 2026.05-2ubuntu3 5 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

A patch is available for this vulnerability. Users should apply the official fixes provided by the Node.js maintainers or their Linux distribution vendors to mitigate the issue. Since this is not a cloud service, remediation depends on applying the patch to affected systems. No alternative mitigations are specified.

Description

A performance degradation vulnerability exists in Node.js's QUIC stream reassembly algorithm, where out-of-order packets cause progressively worse performance with quadratic complexity. This can be exploited by a remote QUIC peer to cause CPU resource exhaustion and potential denial of service with low bandwidth. The issue affects multiple specific Node.js versions and has a CVSS score of 5.3 (low severity). A patch is available.

Impact

A remote attacker who completes the QUIC handshake can exploit this vulnerability to cause significant CPU load on the affected Node.js server, potentially leading to denial of service conditions. This can be achieved with low attacker bandwidth by sending compliant STREAM frames within the advertised receive window. There is no impact on confidentiality or integrity, only availability.

Summary

The QUIC stream reassembly algorithm in Node.js suffers from inefficient handling of out-of-order packets. Specifically, OpenSSL manages received QUIC stream fragments using a doubly-linked list optimized for append operations but falls back to a linear search when fragments do not follow the current tail. An attacker can manipulate packet offsets to force O(n^2) CPU operations, causing excessive CPU consumption and potential denial of service. The vulnerability is tracked as CVE-2026-42772 and is related to CWE-407 (Inefficient Algorithmic Complexity). The FIPS module is unaffected as the QUIC implementation lies outside its boundary.

CWE-407Inefficient Algorithmic Complexity (opens in a new tab)
Class weaknessLikelihood of exploit: Low
An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.
OWASP Cheat Sheets
File Upload (opens in a new tab)
OWASP ASVS 4.0.3
V12.1.1 (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 18 Oct 2026, 06:26 UTC

WeaknessesCWE-407

Technical details

References

Community reviews

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