# What is CVE-2016-10142? > CVE-2016-10142 is a high-severity flaw (CVSS 8.6) in Ipv6 from Ietf, published on 14 January 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 2.8%. If you run an affected version, plan in the vendor’s fix. Canonical page: https://www.precursorintelligence.com/what-is/cve-2016-10142 ## 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:** 47 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes. - **Severity:** High (CVSS 8.6 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:** 2.8% (latest exploit-likelihood forecast) - **Published:** 14 January 2017 - **Record last updated:** 20 April 2025 - **Main product:** Ipv6 from Ietf - **Affected products:** 1 ## What is CVE-2016-10142? 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 take it offline. ### The official description An issue was discovered in the IPv6 protocol specification, related to ICMP Packet Too Big (PTB) messages. (The scope of this CVE is all affected IPv6 implementations from all vendors.) The security implications of IP fragmentation have been discussed at length in [RFC6274] and [RFC7739]. An attacker can leverage the generation of IPv6 atomic fragments to trigger the use of fragmentation in an arbitrary IPv6 flow (in scenarios in which actual fragmentation of packets is not needed) and can subsequently perform any type of fragmentation-based attack against legacy IPv6 nodes that do not implement [RFC6946]. That is, employing fragmentation where not actually needed allows for fragmentation-based attack vectors to be employed, unnecessarily. We note that, unfortunately, even nodes that already implement [RFC6946] can be subject to DoS attacks as a result of the generation of IPv6 atomic fragments. Let us assume that Host A is communicating with Host B and that, as a result of the widespread dropping of IPv6 packets that contain extension headers (including fragmentation) [RFC7872], some intermediate node filters fragments between Host B and Host A. If an attacker sends a forged ICMPv6 PTB error message to Host B, reporting an MTU smaller than 1280, this will trigger the generation of IPv6 atomic fragments from that moment on (as required by [RFC2460]). When Host B starts sending IPv6 atomic fragments (in response to the received ICMPv6 PTB error message), these packets will be dropped, since we previously noted that IPv6 packets with extension headers were being dropped between Host B and Host A. Thus, this situation will result in a DoS scenario. Another possible scenario is that in which two BGP peers are employing IPv6 transport and they implement Access Control Lists (ACLs) to drop IPv6 fragments (to avoid control-plane attacks). If the aforementioned BGP peers drop IPv6 fragments but still honor received ICMPv6 PTB error messages, an attacker could easily attack the corresponding peering session by simply sending an ICMPv6 PTB message with a reported MTU smaller than 1280 bytes. Once the attack packet has been sent, the aforementioned routers will themselves be the ones dropping their own traffic. ### What kind of flaw is it? - Unknown: Unknown ### How an attack on it works - Where an attacker can be: Anywhere on the internet - How hard it is to pull off: Easy: no special conditions - Login needed first: No login needed - Does someone have to click: No, nobody has to do anything - What an attacker gets: Can take it offline Severity vector: `CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H` ## Is CVE-2016-10142 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 2.8%. That can change at any time, which is why we keep watching. Exploit likelihood over the last 7 days: 2.8%, 2.8%, 2.8%, 2.8%, 2.8%, 2.8%, 2.8%. ### Timeline - 14 January 2017: Published - 20 April 2025: Record last updated ### How Precursor Intelligence ranks it CVE-2016-10142 scores **47 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-2016-10142? The published record lists 1 product. - [Ipv6](https://www.precursorintelligence.com/product/ietf/ipv6) by [Ietf](https://www.precursorintelligence.com/vendors/ietf) (Application): version not specified ## How do I fix CVE-2016-10142? 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 latest update from the vendor. The references list where the vendor has published details. 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 - [rhn.redhat.com](http://rhn.redhat.com/errata/RHSA-2017-0817.html) - [securityfocus.com](http://www.securityfocus.com/bid/95797) - [securitytracker.com](http://www.securitytracker.com/id/1038256) - [kb.pulsesecure.net](https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA43730) - [support.f5.com](https://support.f5.com/csp/article/K57211290?utm_source=f5support&%3Butm_medium=RSS) - [tools.ietf.org](https://tools.ietf.org/html/draft-ietf-6man-deprecate-atomfrag-generation-08) (Third-party advisory) - [tools.ietf.org](https://tools.ietf.org/html/rfc8021) (Third-party advisory) ## Questions ### What is CVE-2016-10142? CVE-2016-10142 is a high-severity flaw in Ipv6 from Ietf, published on 14 January 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 take it offline. ### How serious is CVE-2016-10142? It scores 8.6 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2016-10142 is 47 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-2016-10142 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 2.8%. That can change at any time, which is why we keep watching. ### Which versions does CVE-2016-10142 affect? For Ipv6 from Ietf: version not specified. ### How do I fix CVE-2016-10142? Install the update the vendor names in its advisory. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet. ## Does CVE-2016-10142 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. Start free (no card, nothing to install): https://www.precursorintelligence.com/register Book a demo: https://www.precursorintelligence.com/contact