Is CVE-2026-96276 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-96276 being exploited in the wild.

How severe is CVE-2026-96276?

Critical severity, with a CVSS score of 9.8, published 23 September 2026.

Is there a fix for CVE-2026-96276?

A patch was published on 2026: Fixed in v1.18.1 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-96276 attacked?

It is attacked over the network, in a network appliance.

Am I affected by CVE-2026-96276?

Check whether you run Flatpak at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-96276: Flatpak path traversal in build-init extension handling

CVE-2026-96276 · Severity: critical · CVSS 9.8 · Published 2026-09-23

Flatpak is a containerization technology used by developers to build and package applications. When a developer uses a malicious or compromised SDK with the build-init command, an attacker can write arbitrary files outside the intended working directory on the developer's system, potentially compromising the build environment and enabling code injection attacks.

Technologies: Flatpak. Vendors: Flatpak.

Quick answers

Is CVE-2026-96276 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-96276 being exploited in the wild.
How severe is CVE-2026-96276?: Critical severity, with a CVSS score of 9.8, published 23 September 2026.
Which products and versions are affected?: Flatpak before 1.18.1.
Is there a fix for CVE-2026-96276?: A patch was published on 2026: Fixed in v1.18.1 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-96276 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-96276?: Check whether you run Flatpak at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A path traversal vulnerability exists in Flatpak's build-init command when processing SDK extension points with crafted directory paths. The vulnerability allows the `..` directory traversal sequence to bypass pathname restrictions, enabling arbitrary file write operations in the host context. An attacker must provide a malicious SDK container that declares an extension point with a crafted path, and a developer must run `flatpak build-init --writable-sdk --sdk-extension` with that SDK.

Affected products

Flatpak Flatpak before 1.18.1

Timeline

2026-09-23: disclosed
2026: patched: Fixed in v1.18.1

References

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