Unrated

Build-time RCE in Nuclio Java runtime build path

IdentifiersCVE-2026-52833CWE-94

CVE-2026-52833 is a build-time remote code execution vulnerability in Nuclio affecting the Java runtime build path. The flaw arises because attacker-controlled runtimeAttributes.repositories values are inserted verbatim into generated Groovy build.gradle content without proper sanitization or validation. This unsafe templating allows crafted repository values to inject arbitrary Groovy or shell-executed logic during Gradle configuration, resulting in command execution inside the function builder environment. The issue is triggered during Java function builds and affects the integrity of the build pipeline and produced function images.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows an unauthenticated attacker to execute arbitrary operating system commands as root inside the function builder container during Java function builds. An attacker can tamper with build artifacts and resulting function images, access network-reachable resources from the builder environment, and potentially achieve further compromise depending on deployment specifics such as mounted credentials, Kubernetes ServiceAccount privileges, or access to cloud instance metadata. The vulnerability therefore creates both immediate code execution risk and downstream supply-chain risk through poisoned build outputs.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, enable authentication on the Nuclio Dashboard by setting NUCLIO_AUTH_KIND to a non-NOP authenticator, restrict access to the Dashboard service on port 8070 to trusted internal networks, and disable Java runtime support where it is not required. Prefer the kaniko builder over the docker builder to reduce blast radius by avoiding Docker socket exposure. Additional hardening should include minimizing builder container privileges, limiting mounted secrets and ServiceAccount permissions, and restricting outbound network access from build environments.

Remediation

Patch, then assume compromise.

Upgrade Nuclio to version 1.16.5 or later. At the code level, remediation requires strict validation of runtimeAttributes.repositories values against an allowlist of expected repository formats and elimination of unsafe direct rendering into generated build.gradle content. Repository configuration should be constructed through safe structured APIs or escaping mechanisms rather than verbatim template insertion.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

NuclioNuclioapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

No public activity tracked yet. Mallory keeps watching.

0 SOURCESView more in app

No public activity observed for this vulnerability.

What this page doesn’t show

The version that knows your environment.

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Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity