How severe is CVE-2026-33151?

CVE-2026-33151 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-33151 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (40th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-33151?

CVE-2026-33151 affects Socket Socket.io-parser. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-33151?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-33151 have an EU (EUVD) identifier?

Yes. CVE-2026-33151 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-13788.

When was CVE-2026-33151 published?

CVE-2026-33151 was published on 2026-03-20 and last updated on 2026-06-17.

CVE-2026-33151

CVE-2026-33151 is a high-severity vulnerability in Socket Socket.io-parser with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-20.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 8.7
EPSS exploit prediction: 1% (40th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-13788
Weakness: CWE-20
Affected product: Socket Socket.io-parser
Published: 2026-03-20
Last modified: 2026-06-17

Description

Socket.IO is an open source, real-time, bidirectional, event-based, communication framework. Prior to versions 3.3.5, 3.4.4, and 4.2.6, a specially crafted Socket.IO packet can make the server wait for a large number of binary attachments and buffer them, which can be exploited to make the server run out of memory. This issue has been patched in versions 3.3.5, 3.4.4, and 4.2.6.

Frequently asked questions

What is CVE-2026-33151?: Socket.IO is an open source, real-time, bidirectional, event-based, communication framework. Prior to versions 3.3.5, 3.4.4, and 4.2.6, a specially crafted Socket.IO packet can make the server wait for a large number of binary attachments and buffer them, which can be exploited to make the server run out of memory. This issue has been patched in versions 3.3.5, 3.4.4, and 4.2.6.
How severe is CVE-2026-33151?: CVE-2026-33151 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-33151 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (40th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-33151?: CVE-2026-33151 affects Socket Socket.io-parser. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-33151?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-33151 have an EU (EUVD) identifier?: Yes. CVE-2026-33151 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-13788.
When was CVE-2026-33151 published?: CVE-2026-33151 was published on 2026-03-20 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:socket:socket.io-parser:*:*:*:*:*:node.js:*:*

More vulnerabilities in Socket Socket.io-parser

CVE-2022-2421 — Critical (CVSS 10.0): Due to improper type validation in attachment parsing the Socket.io js library, it is possible to overwrite the…
CVE-2020-36049 — High (CVSS 7.5): socket.io-parser before 3.4.1 allows attackers to cause a denial of service (memory consumption) via a large packet…
CVE-2023-32695 — High (CVSS 7.3): socket.io parser is a socket.io encoder and decoder written in JavaScript complying with version 5 of…

All CVEs affecting Socket Socket.io-parser →

Other CWE-20 (Improper Input Validation) vulnerabilities

CVE-2026-48316 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48281 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48277 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48055 — Critical (CVSS 10.0): Streambert is a cross-platform Electron Desktop App to stream and download any video media. In versions 2.4.0 and…
CVE-2026-34910 — Critical (CVSS 10.0): A malicious actor with access to the network could exploit an Improper Input Validation vulnerability found in UniFi OS…
CVE-2026-33587 — Critical (CVSS 10.0): Lack of user input sanitisation in Open Notebook v1.8.3 allows the application user to execute Python code (and…

Browse all CWE-20 (Improper Input Validation) vulnerabilities →