CVE-2019-12521
5.9
MEDIUM
CVSS 3.1
EPSS 0.56%
Description
An issue was discovered in Squid through 4.7. When Squid is parsing ESI, it keeps the ESI elements in ESIContext. ESIContext contains a buffer for holding a stack of ESIElements. When a new ESIElement is parsed, it is added via addStackElement. addStackElement has a check for the number of elements in this buffer, but it's off by 1, leading to a Heap Overflow of 1 element. The overflow is within the same structure so it can't affect adjacent memory blocks, and thus just leads to a crash while processing.
How to fix CVE-2019-12521
To remediate CVE-2019-12521, upgrade the affected package to a fixed version below.
- —upgrade to 4.11-r0 or later
- —upgrade to 4.11-1 or later
Is CVE-2019-12521 being exploited?
Low — EPSS is 0.6%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0, < 4.11-r0
- from 0, < 4.11-1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H |