What is the CVSS score of CVE-2026-70426?

CVE-2026-70426 has a CVSS 3.1 base score of 9.0 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H. EPSS exploitation probability: 0.3%.

Which versions of Jenkins are affected by CVE-2026-70426?

CVE-2026-70426 exposes a critical vulnerability in Jenkins 2.575 and earlier that allows attackers with agent connectivity to gain remote code execution on your Jenkins controller.

How to fix or mitigate CVE-2026-70426?

Within 24 hours: inventory all Jenkins instances running versions 2.575 and earlier (LTS 2.568.1 and earlier) and audit which agents or systems hold Agent/Connect permissions-immediately restrict these to only essential, authenticated, trusted agents, documenting business justification for each. Within 7 days: enable comprehensive logging of agent-controller communications, review historical access patterns from all existing agents for anomalies or unauthorized activity, and validate Remoting library updates in a staging environment. Within 30 days: evaluate and deploy Remoting library backport version 3355.3357.v931d3c992987 or later if available for your environment; monitor vendor advisories for full patch release and establish deployment timeline.

Jenkins CVE-2026-70426

EUVD-2026-53569 CRITICAL

Deserialization of Untrusted Data (CWE-502)

2026-08-05

GHSA-v269-8r2r-vj93

Deserialization Jenkins

9.0

CVSS 3.1 · Vendor

Severity by source

Vendor (CNA) PRIMARY

9.0 CRITICAL

AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

vuln.today AI

9.9 CRITICAL

Network channel exploitation requires Agent/Connect permission (PR:L); scope changes from agent to controller (S:C); full code execution yields C:H/I:H/A:H.

3.1 AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

4.0 AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

Red Hat

8.3 HIGH

qualitative

Primary rating from Vendor (CNA).

CVSS VectorVendor

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Aug 05, 2026 - 16:16 vuln.today

CVE Published

Aug 05, 2026 - 14:02 oss-security

CRITICAL

Description PRE-NVD

Disclosed via oss-security. NVD scoring and full description are pending.

Articles & Coverage 1

News Critical RCE in Jenkins via Remoting Deserialization Filter Bypass - CVE-2026-70426 Aug 05, 2026

AnalysisAI

Remote code execution on the Jenkins controller is achievable by attackers holding Agent/Connect permission via a JEP-200 deserialization filter bypass in the Remoting library (agent.jar/remoting.jar). Jenkins 2.575 and earlier, and LTS 2.568.1 and earlier, include a Remoting version (3384.v60d89463d9e0 and earlier, except the backport 3355.3357.v931d3c992987) that fails to apply the JEP-200 class filter to a fallback deserialization code path, allowing crafted serialized Java objects to reach classes on the Jenkins core classpath that are not blocked by the pre-JEP-200 denylist. No public exploit or CISA KEV listing has been identified at time of analysis, but the primitive - controller-side code execution triggered from an agent - represents a critical trust-boundary violation in Jenkins' controller-agent architecture.

Technical ContextAI

Jenkins uses the Remoting library for controller-agent communication via serialized Java objects over a dedicated channel. To guard against deserialization attacks, Jenkins implemented JEP-200, a class filter allowlist/denylist applied during deserialization on the controller. The flaw resides in a fallback resolution path within the Remoting deserialization implementation that bypasses this filter entirely, exposing classes on the Jenkins core classpath (bundled with Jenkins or the JDK) that are not covered by the pre-JEP-200 denylist. The affected component is Remoting 3384.v60d89463d9e0 and earlier (except the patched backport 3355.3357.v931d3c992987), included in Jenkins core 2.575 and Jenkins LTS 2.568.1. Plugin-bundled dependencies are explicitly not reachable via this path, limiting the gadget surface to core and JDK classes. The root cause class is CWE-502 (Deserialization of Untrusted Data) combined with an incomplete security control - a defense-in-depth bypass rather than a missing control entirely.

RemediationAI

Upgrade Jenkins to 2.576 (weekly) or Jenkins LTS 2.568.2, which include the fixed Remoting version that correctly applies the JEP-200 class filter across all deserialization code paths including the previously unprotected fallback path. The advisory is at https://www.jenkins.io/security/advisory/2026-08-05/. If immediate upgrade is not possible, the primary compensating control is to audit and restrict Agent/Connect permissions to the smallest possible set of trusted principals - revoking this permission from any user or service account that does not strictly require it. Additionally, isolating agent infrastructure so agents can only reach the controller via authenticated, network-segmented channels reduces the blast radius if an agent is compromised by an external party. Note that neither workaround eliminates the vulnerability: a compromised trusted agent can still trigger the bypass. There is no effective application-layer workaround short of upgrading Remoting or Jenkins itself.