CyberSecBulletin
CVE-2026-91145NVD status: Awaiting Analysis

Activiti: Improper Neutralization of Special Elements used in an Expression Language Statement

Published Updated By the CyberSecBulletin desk

CVE-2026-91145 is a high-severity improper neutralization of special elements used in an expression language statement vulnerability in Activiti, with a CVSS 3.1 base score of 7.1 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected Activiti versions: 7.1.0.M6 and earlier. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.42% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of Activiti you run against the affected versions below, and install the vendor's latest release.

Affected products and versions

VendorProductAffected versionsFixed in
ActivitiActiviti7.1.0.M6 and earlierNot stated

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
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
LowLimited modification of data is possible.
Availability
NoneAvailability is not affected.

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N. Scored by CNA (vulncheck.com).

Scoring systemScoreSeverityScored by
CVSS 4.07.1HighCNA (vulncheck.com)
CVSS 3.17.1HighCNA (vulncheck.com)

Official description

Activiti through 7.1.0.M6 fails to validate hash-brace deferred expressions in process variables, allowing attackers to bypass expression filtering. Attackers can inject expressions beginning with #{ that are stored and later evaluated in the full Spring context when a mail task uses variable-backed body fields, enabling method invocation on application beans.

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

The underlying weakness: Improper Neutralization of Special Elements used in an Expression Language Statement

The product constructs all or part of an expression language (EL) statement in a framework such as a Java Server Page (JSP) using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended EL statement before it is executed.

How developers prevent this class of flaw

  • Avoid adding user-controlled data into an expression interpreter when possible.
  • If user-controlled data must be added to an expression interpreter, one or more of the following should be performed: Validate that the user input will not evaluate as an expression Encode the user input in a way that ensures it is not evaluated as an expression
  • The framework or tooling might allow the developer to disable or deactivate the processing of EL expressions, such as setting the isELIgnored attribute for a JSP page to true.

More Improper Neutralization of Special Elements used in an Expression Language Statement vulnerabilities (CWE-917)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Improper Neutralization of Special Elements used in an Expression Language Statement vulnerabilities

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