Buffer overflow in Squid-Cache Squid

CVE-2019-12519

An issue was discovered in Squid through 4.7. When handling the tag esi:when when ESI is enabled, Squid calls ESIExpression::Evaluate. This function uses a fixed stack buffer to hold the expression while it's being evaluated. When processing the expression, it could either evaluate the top of the stack, or add a new member to the stack. When adding a new member, there is no check to ensure that the stack won't overflow.

Vulnerability class: Buffer Overflow

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.067 (93.7th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 94th percentile — 93.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2019-12519: held from 0.066 to 0.067.

EPSS over last 30 days · oldest: 0.066 · newest: 0.067 · change: +0.002

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2019-12519?
CVE-2019-12519 is a critical-severity vulnerability in Squid-Cache Squid, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2020-04-15.
How severe is CVE-2019-12519?
Critical severity. CVSS v3 base score is 9.8 out of 10.