Vulnerability in Golang Crypto
CVE-2019-11841
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N.
EPSS exploit prediction
EPSS: 0.020 (80.4th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 80th percentile — 80.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.020 · newest: 0.020 · change: 0.000
Affected products
- Golang Crypto — versions 2019-03-25
- Debian Linux — versions 8.0, 9.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- sec-consult.com/ (Third Party Advisory)
- go.googlesource.com/crypto/ (Product, Third Party Advisory)
- packetstormsecurity.com/files/152840/Go-Cryptography-Libraries-Cleartext-Messag… (Exploit, VDB Entry, Third Party Advisory)
- sec-consult.com/en/blog/advisories/cleartext-message-spoofing-in-go-cryptograph… (Exploit, Third Party Advisory)
- lists.debian.org/debian-lts-announce/2019/09/msg00011.html (mailing-list, Mailing List, Third Party Advisory)
- lists.debian.org/debian-lts-announce/2020/10/msg00014.html (mailing-list, Mailing List, Third Party Advisory)
- lists.debian.org/debian-lts-announce/2023/06/msg00017.html (mailing-list)
Frequently asked questions
- What is CVE-2019-11841?
- CVE-2019-11841 is a medium-severity vulnerability in Golang Crypto, classified under Improper Verification of Cryptographic Signature. CVSS score: 5.9/10. Published 2019-05-22.
- How severe is CVE-2019-11841?
- Medium severity. CVSS v3 base score is 5.9 out of 10.
- Is CVE-2019-11841 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.