Jenkins patched a critical RCE flaw in its open source automation server
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2017-1000353 | Unauthenticated Deserialization RCE in Jenkins CLI (≤2.56 / ≤2.46.1 LTS) CVE-2017-1000353 is an unauthenticated remote code execution flaw in the Jenkins CLI (CWE-502): an attacker can send a crafted serialized Java SignedObject to the remoting-based CLI endpoint, where it is deserialized with a new ObjectInputStream and bypasses Jenkins' existing blacklist-based deserialization protection. Triggering it requires only network reachability to the Jenkins remoting CLI — no authentication or user interaction — which is why the flaw scores 9.8 (critical) under CVSS 3.1. Successful exploitation gives arbitrary code execution with the privileges of the Jenkins process, i.e., full control of the CI/CD server and any credentials, source code, and build infrastructure it holds; Jenkins servers have historically been targeted for cryptomining campaigns such as JenkinsMiner, which reportedly generated $3.4 million. All Jenkins versions 2.56 and earlier and 2.46.1 LTS and earlier are affected, including Oracle Communications Cloud Native Core Automated Test Suite deployments that bundle affected Jenkins releases. Exploitation status is serious: a public proof-of-concept exploit exists (Exploit-DB 41965), EPSS estimates a 99.7% probability of exploitation within 30 days, and CISA added the flaw to its Known Exploited Vulnerabilities catalog on 2025-10-02. Do: Upgrade to Jenkins 2.57 or later (weekly line) or 2.46.2 LTS or later, which add SignedObject to the deserialization blacklist, backport the HTTP CLI protocol, and deprecate/disable the remoting (Java serialization) CLI by default; as an interim mitigation, disable or restrict access to the remoting CLI (e.g., the /cli endpoint) from untrusted networks. Because the flaw is in CISA's KEV catalog, federal agencies must apply vendor mitigations or discontinue use per BOD 22-01, and all administrators of internet-facing Jenkins instances should check for signs of compromise such as cryptomining processes. Oracle Communications Cloud Native Core Automated Test Suite users should apply the applicable Oracle security patch/update addressing CVE-2017-1000353. | 9.8 group max | 100% | KEV PoC |
| mass≈1,000,000+ users / hundreds of thousands of installations, with tens of thousands of instances historically exposed to the internet |
Full article354 words · extracted from securityaffairs.com · click to collapse
Jenkins developers fixed a critical RCE vulnerability in the popular open source automation server along with many other issues.
Jenkins is the most popular open source automation server, it is maintained by CloudBees and the Jenkins community.
The automation server supports developers build, test and deploy their applications, it has more than 133,000 active installations worldwide with more than 1 million users.
The developers of the automation server recently patched several vulnerabilities, including a critical flaw that can be exploited by a remote attacker for arbitrary code execution.
A security researcher recently reported to the Beyond Security’s SecuriTeam Secure Disclosure program that the popular automation server is affected by a critical issue related to Java deserialization.
The vulnerability could be exploited by a remote unauthenticated attacker to execute arbitrary code on the target system, a hacker just needs to send two specially crafted requests to the affected server.
“CLI: Unauthenticated remote code execution
SECURITY-429 / CVE-2017-1000353
An unauthenticated remote code execution vulnerability allowed attackers to transfer a serialized Java SignedObject object to the remoting-based Jenkins CLI, which would be deserialized using a new ObjectInputStream, bypassing the existing blacklist-based protection mechanism.
SignedObject has been added to the remoting blacklist.” reads the security advisory published by Jenkins.
Jenkins developers admitted that the flaw “allowed attackers to transfer a serialized Java SignedObject object to the remoting-based Jenkins CLI, that would be deserialized using a new ObjectInputStream, bypassing the existing blacklist-based protection mechanism.”
The development team released versions 2.57 and 2.46.2 (LTS) to address the issue. The security updates also fixed other problems, such as multiple high severity cross-site request forgery (CSRF) vulnerabilities and high-severity cross-site request forgery (CSRF) vulnerabilities.
According to the development team, the CSRF flaws can be exploited by attackers to conduct several malicious activities such as restarting the server and installing plugins.
The security updates also fixed a Login command that allowed to impersonate any Jenkins user (SECURITY-466 / CVE-2017-1000354) and an XStream issue that could cause Java crash when trying to instantiate void/Void (SECURITY-503 / CVE-2017-1000355).
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(Security Affairs – automation server, hacking)
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