PatchTheCVECVE-2020-23921: An issue was discovered in fast_ber through v0.4
CVE-2020-23921 is a high-severity flaw (CVSS 7.1) affecting fast ber. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
An issue was discovered in fast_ber through v0.4. yy::yylex() in asn_compiler.hpp has a heap-based buffer over-read.
Why this priority
- High severity
- Public exploit reference
A fixed release or distro patch exists.
Risk facts
| CVSS score | 7.1 (High) |
| Attack vector | Local |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | Required |
| EPSS exploit chance | 0.9% (top 40%) |
| CISA exploited list | No |
| Weakness | CWE-125 |
| Published | 2021-04-21 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2020-23921?
fast ber: upgrade to newer than 0.4. Exact commands for each OS are on this page.
Is CVE-2020-23921 being exploited?
CVE-2020-23921 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2020-23921 affect?
CVE-2020-23921 affects fast ber. Severity is high (CVSS 7.1). An issue was discovered in fast_ber through v0.4. yy::yylex() in asn_compiler.hpp has a heap-based buffer over-read.
How urgent is CVE-2020-23921?
Priority 45/100. High severity; Public exploit reference