CyberSecBulletin
CVE-2026-116366NVD status: Awaiting Analysis

ClickHouse: Integer Overflow or Wraparound

Published Updated By the CyberSecBulletin desk

CVE-2026-116366 is a critical-severity integer overflow or wraparound vulnerability in ClickHouse, with a CVSS 4.0 base score of 9.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 26.3.62.3-lts, 26.8.36.3-lts, 26.9.27.3-stable as the first without the flaw, so updating ClickHouse to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.96% chance of exploitation within 30 days, higher than 62% of scored CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update ClickHouse to 26.3.62.3-lts or 26.8.36.3-lts or 26.9.27.3-stable or 26.10.3.7-stable, whichever matches your release line, or a later version.
  2. Update ClickHouse Cloud to 25.12.1.1713 or 26.2.1.835 or 26.4.1.2704 or 26.6.1.2439, whichever matches your release line, or a later version.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
ClickHouseClickHouse26.3 up to, but not including, 26.3.62.3-lts; 26.8 up to, but not including, 26.8.36.3-lts; 26.9 up to, but not including, 26.9.27.3-stable; 26.10 up to, but not including, 26.10.3.7-stable26.3.62.3-lts, 26.8.36.3-lts, 26.9.27.3-stable, 26.10.3.7-stable
ClickHouseClickHouse Cloud25.12 up to, but not including, 25.12.1.1713; 26.2 up to, but not including, 26.2.1.835; 26.4 up to, but not including, 26.4.1.2704; 26.6 up to, but not including, 26.6.1.2439; 26.8 up to, but not including, 26.8.1.597; 26.10 up to, but not including, 26.10.2.8425.12.1.1713, 26.2.1.835, 26.4.1.2704, 26.6.1.2439, 26.8.1.597, 26.10.2.84

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
HighSuccess depends on conditions outside the attacker's control.
Attack requirements
NoneThe attack does not depend on a particular deployment or configuration.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Confidentiality (vulnerable system)
HighSerious loss of confidentiality on the vulnerable system.
Integrity (vulnerable system)
HighSerious loss of integrity on the vulnerable system.
Availability (vulnerable system)
HighSerious loss of availability on the vulnerable system.
Confidentiality (other systems)
HighSerious loss of confidentiality on systems beyond the vulnerable one.
Integrity (other systems)
HighSerious loss of integrity on systems beyond the vulnerable one.
Availability (other systems)
HighSerious loss of availability on systems beyond the vulnerable one.

Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. Scored by CNA.

Official description

An issue has been discovered in ClickHouse Server that, under certain conditions, could allow an unauthenticated user with network access to execute arbitrary code on the ClickHouse Server.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Integer Overflow or Wraparound

The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

How developers prevent this class of flaw

  • Ensure that all protocols are strictly defined, such that all out-of-bounds behavior can be identified simply, and require strict conformance to the protocol.
  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. If possible, choose a language or compiler that performs automatic bounds checking.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Use libraries or frameworks that make it easier to handle numbers without unexpected consequences. Examples include safe integer handling packages such as SafeInt (C++) or IntegerLib (C or C++).

More Integer Overflow or Wraparound vulnerabilities (CWE-190)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).

References

Other vulnerabilities in ClickHouse

All ClickHouse vulnerabilities

Recent Integer Overflow or Wraparound vulnerabilities

Spotted an error? Tell us.