CVE-2019-11841 Golang/x/crypto message forgery vulnerability
Attackers can spoof OpenPGP signature headers and prepend arbitrary text to cleartext messages without invalidating signatures, bypassing integrity checks.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2019-11841?
CVE-2019-11841 is a medium-severity vulnerability in Debian Debian Linux, published on 22 May 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-347
Which versions are affected by CVE-2019-11841?
3 open source packages ship an affected version, including golang.org/x/crypto. It affects 2 products.
| Package | Affected | Fixed in |
|---|---|---|
golang.org/x/crypto Go | All versions | 0.0.0-20190424203555-c05e17bb3b2d |
golang.org/x/crypto Go | All versions | 0.0.0-20190424203555-c05e17bb3b2d |
golang.org/x/crypto Go | All versions | 0.0.0-20190424203555-c05e17bb3b2d |
Products include Debian Debian Linux, Golang Crypto.
How do I fix CVE-2019-11841?
Upgrade golang.org/x/crypto to 0.0.0-20190424203555-c05e17bb3b2d or later.
Is CVE-2019-11841 being exploited?
There is no known exploitation of CVE-2019-11841 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as DEBIAN-CVE-2019-11841, DLA-1920-1, GHSA-x3jr-pf6g-c48f, GO-2023-1992, UBUNTU-CVE-2019-11841.