Klaviyo password bug: risk for e-commerce and marketing automation

What happened: the Klaviyo bug in a nutshell

On August 10, 2026, TechCrunch has reported the discovery of a bug on the Klaviyo website. The vulnerability exposed the passwords of new subscribers to the platform. Specifically, dozens of advertisers connected to the ecosystem could have viewed plain text credentials.

Klaviyo is one of the most popular marketing automation platforms globally. It's used by e-commerce, retailers, and B2B companies to manage email campaigns, SMS, and automated nurturing flows. Therefore, the potential scope of the incident is significant.

At the time of publication, complete technical details had not yet been made public by the company. However, the nature of the bug—related to the registration process—suggests an issue with data handling in transit or insecure logging.

Immediate impact on email and SMS marketing strategies

For marketing managers using Klaviyo, the impact is twofold. First of all, there is a direct risk linked to account compromise. Unauthorized access to the platform can alter automated flows, export contact lists, or modify active campaigns.

Furthermore, the risk extends to brand reputation. Recipients of email and SMS communications expect their data to be handled securely. Consequently, such an incident can erode the trust built over time through campaigns. Digital marketing structured.

Finally, the regulatory impact must be considered. GDPR imposes strict obligations in the event of a data breach. Companies using Klaviyo as a data processor need to assess whether the incident falls within the thresholds for notifying the supervisory authority within 72 hours.

The risk profile for Italian SMEs and retailers

Klaviyo is particularly popular among Italian e-commerce SMEs. Many integrate it with platforms like Shopify, WooCommerce, or Magento. Therefore, the potential attack surface is large even in the domestic market.

Automation platforms are currently one of the priority investments for mid-market companies. However, the security of these tools is often superficially evaluated during vendor selection.

We at SHM Studio We frequently observe this dynamic. Companies choose the platform for its segmentation features or native integration with the CMS. Conversely, security criteria — two-factor authentication, permission management, audit logs — are considered secondary. This episode shows that this approach needs to be revisited.

What to do now: top priority actions for marketing teams

The operational response to an incident like this requires speed and method. Below are the most urgent actions for marketing and digital managers who use Klaviyo.

• Change your password right away: all users who have recently created or updated a Klaviyo account must change their credentials without waiting for official communications.
• Turn on two-factor authentication (2FA): if not already enabled, is the most effective measure to limit damage in case of compromised credentials.
• Access Audit: check the platform's access logs to spot any weird or unrecognised sessions.
• Review user permissions: limit access only to the functions needed by each team member. Shrink the exposed surface area.
• Check active automations: check that email and SMS flows have not been altered. In particular, verify welcome sequences and transactional triggers.
• GDPR Assessment: involve the company DPO to determine if the incident requires notification to the Italian Data Protection Authority.

In addition to this, it is advisable to internally communicate what happened to the team. Crisis management starts with shared awareness, not downplaying.

SaaS platform security: a structural issue

The Klaviyo case is not an isolated incident. In recent years, numerous marketing SaaS platforms have suffered similar vulnerabilities. In fact, the complexity of modern tech stacks—API integrations, webhooks, tracking pixels—multiplies the exposure points.

Vendor due diligence cannot be limited to functionalities: it must include security posture, disclosure policy, and incident history.

Similarly, choosing to rely on a single platform for email, SMS, and automation concentrates the risk. A diversification strategy—or at least an operational backup—reduces dependence on a single point of failure.

For anyone running campaigns through LinkedIn Ads or Google Ads with audiences synced from Klaviyo, the risk also extends to remarketing lists. It is therefore necessary to verify that the integrations have not been tampered with.

The agency’s perspective: what people often don't say

Incidents like this reveal a structural tension in the marketing technology market. On one hand, platforms compete on features, UX, and integrations. On the other hand, security often remains a secondary differentiator in the sales pitch.

However, for a marketing manager, platform security is also a matter of operational continuity. A compromised account can block active campaigns, alter analytical data, and generate unauthorized communications to one's contacts. Therefore, the real cost of an incident far exceeds that of a preventive investment in security.

Here at SHM Studio, when we support clients in selecting or optimizing their stack of marketing automation and AI , we always include an assessment of the vendor's security posture. Not as an accessory element, but as a primary criterion. Because a strategy SEO solid or a campaign of content well-structured ones lose value if the distribution channel is vulnerable.

Outlook: what awaits us in the coming months

Klaviyo will face a path of transparency and remediation. Publicly traded companies—Klaviyo went public on the NYSE in 2023—are subject to disclosure obligations that will make opaque management of the incident difficult.

Furthermore, the episode is likely to accelerate the conversation on security in marketing automation. Between 2027 and 2028, we expect security certification criteria (SOC 2, ISO 27001) to become standard requirements in RFPs from Italian mid-market companies when selecting SaaS platforms.

For marketing teams, this is the right time to kick off a review of their tech stack. Not in an emergency mode, but a strategic one. The documentation and continuous updates on industry trends are a key part of mature management of Digital .

Anyone wanting to dive deeper into how to set up a secure and high-performing marketing automation stack can contact the SHM Studio team for a no-obligation initial assessment.