# What is CVE-2019-11841? > CVE-2019-11841 is a medium-severity flaw (CVSS 5.9) in Crypto from Golang, published on 22 May 2019. 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 2.0%. If you run an affected version, plan in the vendor’s fix. Canonical page: https://www.precursorintelligence.com/what-is/cve-2019-11841 ## 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:** 42 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes. - **Severity:** Medium (CVSS 5.9 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:** 2.0% (latest exploit-likelihood forecast) - **Published:** 22 May 2019 - **Record last updated:** 17 June 2023 - **Main product:** Crypto from Golang - **Affected products:** 2 ## What is CVE-2019-11841? 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 change data. ### The official description A message-forgery issue was discovered in crypto/openpgp/clearsign/clearsign.go in supplementary Go cryptography libraries 2019-03-25. According to the OpenPGP Message Format specification in RFC 4880 chapter 7, a cleartext signed message can contain one or more optional "Hash" Armor Headers. The "Hash" Armor Header specifies the message digest algorithm(s) used for the signature. However, the Go clearsign package ignores the value of this header, which allows an attacker to spoof it. Consequently, an attacker can lead a victim to believe the signature was generated using a different message digest algorithm than what was actually used. Moreover, since the library skips Armor Header parsing in general, an attacker can not only embed arbitrary Armor Headers, but also prepend arbitrary text to cleartext messages without invalidating the signatures. ### What kind of flaw is it? - CWE-347: Improper Verification of Cryptographic Signature ### 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 change data Severity vector: `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N` ## Is CVE-2019-11841 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 2.0%. That can change at any time, which is why we keep watching. Exploit likelihood over the last 7 days: 2.0%, 2.0%, 2.0%, 2.0%, 2.0%, 2.0%, 2.0%. ### Timeline - 22 May 2019: Published - 17 June 2023: Record last updated ### How Precursor Intelligence ranks it CVE-2019-11841 scores **42 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-2019-11841? The published record lists 2 products. - [Crypto](https://www.precursorintelligence.com/product/golang/crypto) by [Golang](https://www.precursorintelligence.com/vendors/golang) (Application): 2019-03-25 - [Debian Linux](https://www.precursorintelligence.com/product/debian/debian_linux) by [Debian](https://www.precursorintelligence.com/vendors/debian) (Operating system): 8.0, 9.0 ## How do I fix CVE-2019-11841? 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 - [packetstormsecurity.com](http://packetstormsecurity.com/files/152840/Go-Cryptography-Libraries-Cleartext-Message-Spoofing.html) (Exploit, Third-party advisory, Vulnerability database) - [go.googlesource.com](https://go.googlesource.com/crypto/) (Product, Third-party advisory) - [lists.debian.org](https://lists.debian.org/debian-lts-announce/2019/09/msg00011.html) (Mailing list, Third-party advisory) - [lists.debian.org](https://lists.debian.org/debian-lts-announce/2020/10/msg00014.html) (Mailing list, Third-party advisory) - [lists.debian.org](https://lists.debian.org/debian-lts-announce/2023/06/msg00017.html) - [sec-consult.com](https://sec-consult.com/) (Third-party advisory) - [sec-consult.com](https://sec-consult.com/en/blog/advisories/cleartext-message-spoofing-in-go-cryptography-libraries-cve-2019-11841/) (Exploit, Third-party advisory) ## Questions ### What is CVE-2019-11841? CVE-2019-11841 is a medium-severity flaw in Crypto from Golang, published on 22 May 2019. It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can change data. ### How serious is CVE-2019-11841? It scores 5.9 out of 10 on the CVSS severity scale, which is medium. Our risk score for CVE-2019-11841 is 42 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-2019-11841 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 2.0%. That can change at any time, which is why we keep watching. ### Which versions does CVE-2019-11841 affect? For Crypto from Golang: 2019-03-25. The record lists 2 products in all, each with its versions, under "Who is affected" on this page. ### How do I fix CVE-2019-11841? 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-2019-11841 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