Vulnerability Details : CVE-2021-20235
There's a flaw in the zeromq server in versions before 4.3.3 in src/decoder_allocators.hpp. The decoder static allocator could have its sized changed, but the buffer would remain the same as it is a static buffer. A remote, unauthenticated attacker who sends a crafted request to the zeromq server could trigger a buffer overflow WRITE of arbitrary data if CURVE/ZAP authentication is not enabled. The greatest impact of this flaw is to application availability, data integrity, and confidentiality.
Vulnerability category: OverflowMemory Corruption
Products affected by CVE-2021-20235
- cpe:2.3:a:zeromq:libzmq:*:*:*:*:*:*:*:*
Exploit prediction scoring system (EPSS) score for CVE-2021-20235
0.66%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 79 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2021-20235
| Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
|---|---|---|---|---|---|---|
|
6.8
|
MEDIUM | AV:N/AC:M/Au:N/C:P/I:P/A:P |
8.6
|
6.4
|
NIST | |
|
8.1
|
HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H |
2.2
|
5.9
|
NIST |
CWE ids for CVE-2021-20235
-
The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow.Assigned by: secalert@redhat.com (Secondary)
-
The product writes data past the end, or before the beginning, of the intended buffer.Assigned by:
- nvd@nist.gov (Primary)
- secalert@redhat.com (Secondary)
References for CVE-2021-20235
-
https://github.com/zeromq/libzmq/security/advisories/GHSA-fc3w-qxf5-7hp6
Heap overflow when receiving malformed ZMTP v1 packets (CURVE disabled) · Advisory · zeromq/libzmq · GitHubPatch;Third Party Advisory
-
https://bugzilla.redhat.com/show_bug.cgi?id=1921983
1921983 – (CVE-2021-20235) CVE-2021-20235 zeromq: Heap overflow when receiving malformed ZMTP v1 packetsIssue Tracking;Patch;Third Party Advisory
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