# What is CVE-2017-4995?

> CVE-2017-4995 is a high-severity flaw (CVSS 8.1) in Spring Security from VMware, published on 27 November 2017. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 2.5%. If you run an affected version, plan in the vendor’s fix.

Canonical page: https://www.precursorintelligence.com/what-is/cve-2017-4995

## At a glance

- **Verdict:** Plan it in. No sign of exploitation and a low forecast. Patch it in your normal update cycle.
- **Precursor Intelligence risk score:** 40 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes.
- **Severity:** High (CVSS 8.1 out of 10)
- **Known to be exploited:** No, not on the list of flaws known to be exploited today
- **Chance of use in the next 30 days:** 2.5% (latest exploit-likelihood forecast)
- **Published:** 27 November 2017
- **Record last updated:** 20 April 2025
- **Main product:** Spring Security from VMware
- **Affected products:** 1

## What is CVE-2017-4995? In plain terms

It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can read data, change data and take it offline.

### The official description

An issue was discovered in Pivotal Spring Security 4.2.0.RELEASE through 4.2.2.RELEASE, and Spring Security 5.0.0.M1. When configured to enable default typing, Jackson contained a deserialization vulnerability that could lead to arbitrary code execution. Jackson fixed this vulnerability by blacklisting known "deserialization gadgets." Spring Security configures Jackson with global default typing enabled, which means that (through the previous exploit) arbitrary code could be executed if all of the following is true: (1) Spring Security's Jackson support is being leveraged by invoking SecurityJackson2Modules.getModules(ClassLoader) or SecurityJackson2Modules.enableDefaultTyping(ObjectMapper); (2) Jackson is used to deserialize data that is not trusted (Spring Security does not perform deserialization using Jackson, so this is an explicit choice of the user); and (3) there is an unknown (Jackson is not blacklisting it already) "deserialization gadget" that allows code execution present on the classpath. Jackson provides a blacklisting approach to protecting against this type of attack, but Spring Security should be proactive against blocking unknown "deserialization gadgets" when Spring Security enables default typing.

### What kind of flaw is it?

- CWE-502: Deserialization of Untrusted Data

### How an attack on it works

- Where an attacker can be: Anywhere on the internet
- How hard it is to pull off: Hard: conditions must line up
- Login needed first: No login needed
- Does someone have to click: No, nobody has to do anything
- What an attacker gets: Can read data, change data and take it offline

Severity vector: `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`

## Is CVE-2017-4995 being exploited? Not that we know of

It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 2.5%. That can change at any time, which is why we keep watching.

Exploit likelihood over the last 7 days: 2.5%, 2.5%, 2.5%, 2.5%, 2.5%, 2.5%, 2.5%.

### Timeline

- 27 November 2017: Published
- 20 April 2025: Record last updated

### How Precursor Intelligence ranks it

CVE-2017-4995 scores **40 out of 100 (Medium)**, with the action "Plan remediation".

Every published flaw gets a risk score from 0 to 100, kept up to date as the evidence changes. Four things go into the score, from the one that counts most to the ones that count less:

- Evidence it is being exploited: biggest factor
- How severe it is: strong factor
- How widely exposed it is: smaller factor
- Threat activity around it: smaller factor

85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score. When this flaw matches software you track, it lands in your list with its score and the reasons behind it.

## Who is affected by CVE-2017-4995?

The published record lists 1 product.

- [Spring Security](https://www.precursorintelligence.com/product/vmware/spring_security) by [VMware](https://www.precursorintelligence.com/vendors/vmware) (Application): 4.2.0-release, 4.2.1-release, 4.2.2-release, 5.0.0-m1

## How do I fix CVE-2017-4995?

1. **Check whether you run it.** Compare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list.
2. **Apply the vendor’s fix.** Install the update named in the vendor’s advisory. We’ve put the advisory first in the list.
3. **If you can’t patch today.** Follow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in.
4. **Keep an eye on it.** Track the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood.

### References

- [pivotal.io](https://pivotal.io/security/cve-2017-4995) (Issue tracking, Vendor advisory)
- [securityfocus.com](http://www.securityfocus.com/bid/99080) (Broken link)
- [lists.apache.org](https://lists.apache.org/thread.html/4641ed8616ccc2c1fbddac2c3dc9900c96387bc226eaf0232d61909b%40%3Ccommits.cassandra.apache.org%3E)
- [lists.apache.org](https://lists.apache.org/thread.html/r42ac3e39e6265db12d9fc6ae1cd4b5fea7aed9830dc6f6d58228fed7%40%3Ccommits.cassandra.apache.org%3E)
- [lists.apache.org](https://lists.apache.org/thread.html/rf7f87810c38dc9abf9f93989f76008f504cbf7c1a355214640b2d04c%40%3Ccommits.cassandra.apache.org%3E)

## Questions

### What is CVE-2017-4995?

CVE-2017-4995 is a high-severity flaw in Spring Security from VMware, published on 27 November 2017. It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can read data, change data and take it offline.

### How serious is CVE-2017-4995?

It scores 8.1 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2017-4995 is 40 out of 100, which is Medium. Its action is "Plan remediation". No sign of exploitation and a low forecast. Patch it in your normal update cycle.

### Is CVE-2017-4995 being exploited?

It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 2.5%. That can change at any time, which is why we keep watching.

### Which versions does CVE-2017-4995 affect?

For Spring Security from VMware: 4.2.0-release, 4.2.1-release, 4.2.2-release, 5.0.0-m1.

### How do I fix CVE-2017-4995?

Install the update the vendor names in its advisory, linked first under "How do I fix" on this page. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet.

## Does CVE-2017-4995 affect you?

Precursor Intelligence keeps checking for you:

- **Tell us what you run.** Pick your software from a list, or let us work it out from your website.
- **We match it to every flaw.** Over 400,000 published flaws, checked against your list.
- **Ranked by real-world risk.** Every flaw gets a 0 to 100 risk score, kept up to date, led by evidence criminals are using it.
- **Told as soon as we know.** An alert by email, in the app or by webhook to your own tools.

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