Vulnerability · Published Jun 11, 2021 · Assigned by hackerone
CVE-2021-22901
High 8.1
In plain English
A high-severity use-after-free in https://github.com/curl/curl. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 63.5% (higher than 99.2% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
curl 7.75.0 through 7.76.1 suffers from a use-after-free vulnerability resulting in already freed memory being used when a TLS 1.3 session ticket arrives over a connection. A malicious server can use this in rare unfortunate circumstances to potentially reach remote code execution in the client. When libcurl at run-time sets up support for TLS 1.3 session tickets on a connection using OpenSSL, it stores pointers to the transfer in-memory object for later retrieval when a session ticket arrives. If the connection is used by multiple transfers (like with a reused HTTP/1.1 connection or multiplexed HTTP/2 connection) that first transfer object might be freed before the new session is established on that connection and then the function will access a memory buffer that might be freed. When using that memory, libcurl might even call a function pointer in the object, making it possible for a remote code execution if the server could somehow manage to get crafted memory content into the correct place in memory.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | curl | 7.77.0-r0 | ALPINE-CVE-2021-22901 |
| Alpine:v3.21 | curl | 7.77.0-r0 | ALPINE-CVE-2021-22901 |
| Alpine:v3.22 | curl | 7.77.0-r0 | ALPINE-CVE-2021-22901 |
| Alpine:v3.23 | curl | 7.77.0-r0 | ALPINE-CVE-2021-22901 |
| Alpine:v3.24 | curl | 7.77.0-r0 | ALPINE-CVE-2021-22901 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| n/a | https://github.com/curl/curl | 7.75.0 through 7.76.1 |
Weakness: CWE-416
References
- https://hackerone.com/reports/1180380 x_refsource_MISC
- https://curl.se/docs/CVE-2021-22901.html x_refsource_MISC
- https://github.com/curl/curl/commit/7f4a9a9b2a49547eae24d2e19bc5c346e9026479 x_refsource_MISC
- https://www.oracle.com//security-alerts/cpujul2021.html x_refsource_MISC
- https://security.netapp.com/advisory/ntap-20210723-0001/ x_refsource_CONFIRM
- https://www.oracle.com/security-alerts/cpujan2022.html x_refsource_MISC
- https://security.netapp.com/advisory/ntap-20210727-0007/ x_refsource_CONFIRM
- https://www.oracle.com/security-alerts/cpuapr2022.html x_refsource_MISC
- https://cert-portal.siemens.com/productcert/pdf/ssa-389290.pdf x_refsource_CONFIRM
- https://cert-portal.siemens.com/productcert/pdf/ssa-732250.pdf x_refsource_CONFIRM
- https://cert-portal.siemens.com/productcert/html/ssa-389290.html
- https://cert-portal.siemens.com/productcert/html/ssa-732250.html
- https://cert-portal.siemens.com/productcert/html/ssa-398330.html