7.5

CVE-2026-102599: socketio socket.io Uncaught Exception

CVSS: 7.5v3.1HighAwaiting analysis
AliasesCGA-8xwx-8489-hpfmCGA-rxw2-rv4r-9w98GHSA-2gc4-cqfq-p2gv
Published 13-10-2026Last modified 17-10-2026
Open JSON

Vulnerability summary

CVE-2026-102599 is a high (CVSS 7.5) Uncaught Exception vulnerability in socketio socket.io. EPSS estimates a 0.58% chance of exploitation in the next 30 days, higher than 46.7% of scored vulnerabilities.

Overall risk
30/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
0.58%
0%100%
Low · Change unavailable
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 13-10-2026
    PublishedVulnerability first disclosed.
  2. 17-10-2026
    Last modifiedVulnerability information updated.

Description

Socket.IO enables bidirectional and low-latency communication for every platform. From Engine.IO 6.6.0 until 6.6.10, a transport upgrade can independently derive an Engine.IO protocol revision from the upgrade request instead of enforcing the revision stored on the existing session. A malicious client can establish a valid session and send an upgrade request with a different or omitted EIO query parameter, attaching a transport with incompatible parser and heartbeat behavior. A crafted heartbeat packet can then trigger an uncaught exception and terminate the Node.js process, including when Engine.IO v3 compatibility is disabled because an omitted EIO value is interpreted as revision 3 on the affected path. This issue is fixed in Engine.IO 6.6.10.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.58%

Chance of exploitation in the next 30 days

Percentile

47%

Versus all other CVEs

30-day change

Change unavailable

Change unavailable

14-10-202618-10-2026
EPSS score
0.58%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Chainguard14 products
  • commercial-gitlab-rails-ee-19.2< 19.2.7-r1
  • commercial-gitlab-rails-ee-19.3< 19.3.3-r1
  • commercial-gitlab-rails-ee-19.4< 19.4.1-r1
  • commercial-gitlab-rails-ee-fips-19.2< 19.2.7-r1
  • commercial-gitlab-rails-ee-fips-19.3< 19.3.3-r1
Npm1 product
  • engine.io≥ 6.6.0, < 6.6.10
Socketio1 product
Wolfi1 product
  • jupyter-base-notebook< 7.6.3-r2

4 vendors · 17 products

References

4 links