Vulnerability · Published Apr 1, 2021 · Assigned by hackerone
CVE-2021-22890
Medium 4.3
In plain English
A medium-severity security flaw in https://github.com/curl/curl. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 3.1% (higher than 88% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
curl 7.63.0 to and including 7.75.0 includes vulnerability that allows a malicious HTTPS proxy to MITM a connection due to bad handling of TLS 1.3 session tickets. When using a HTTPS proxy and TLS 1.3, libcurl can confuse session tickets arriving from the HTTPS proxy but work as if they arrived from the remote server and then wrongly "short-cut" the host handshake. When confusing the tickets, a HTTPS proxy can trick libcurl to use the wrong session ticket resume for the host and thereby circumvent the server TLS certificate check and make a MITM attack to be possible to perform unnoticed. Note that such a malicious HTTPS proxy needs to provide a certificate that curl will accept for the MITMed server for an attack to work - unless curl has been told to ignore the server certificate check.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | curl | 7.76.0-r0 | ALPINE-CVE-2021-22890 |
| Alpine:v3.21 | curl | 7.76.0-r0 | ALPINE-CVE-2021-22890 |
| Alpine:v3.22 | curl | 7.76.0-r0 | ALPINE-CVE-2021-22890 |
| Alpine:v3.23 | curl | 7.76.0-r0 | ALPINE-CVE-2021-22890 |
| Alpine:v3.24 | curl | 7.76.0-r0 | ALPINE-CVE-2021-22890 |
| Debian:12 | curl | 7.74.0-1.2 | DEBIAN-CVE-2021-22890 |
| Debian:13 | curl | 7.74.0-1.2 | DEBIAN-CVE-2021-22890 |
| Debian:14 | curl | 7.74.0-1.2 | DEBIAN-CVE-2021-22890 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| n/a | https://github.com/curl/curl | 7.63.0 to and including 7.75.0 |
Weakness: CWE-300 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
References
- https://hackerone.com/reports/1129529 x_refsource_MISC
- https://curl.se/docs/CVE-2021-22890.html x_refsource_MISC
- FEDORA-2021-cab5c9befb vendor-advisory, x_refsource_FEDORA
- FEDORA-2021-065371f385 vendor-advisory, x_refsource_FEDORA
- FEDORA-2021-26a293c72b vendor-advisory, x_refsource_FEDORA
- GLSA-202105-36 vendor-advisory, x_refsource_GENTOO
- https://www.oracle.com//security-alerts/cpujul2021.html x_refsource_MISC
- https://security.netapp.com/advisory/ntap-20210521-0007/ x_refsource_CONFIRM
- https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf x_refsource_CONFIRM
- https://cert-portal.siemens.com/productcert/html/ssa-389290.html
- https://cert-portal.siemens.com/productcert/html/ssa-398330.html