CVE & CISA-KEV Catalog

CVE-2019-12521

MEDIUMEPSS 92th pctl
5.9
CVSS v3
NVD

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.

CWE-193CWE-787Out-of-bounds Write

How to fix

Remediation Available
squidDebian
Fixed in:4.11-1CVE-2019-12521
Fixed in:4.11-1CVE-2019-12521
Fixed in:4.11-1CVE-2019-12521
Fixed in:4.11-1CVE-2019-12521
squidUbuntu
Fixed in:3.5.12-1ubuntu7.11USN-4356-1
Fixed in:3.5.27-1ubuntu1.6USN-4356-1
Fixed in:4.10-1ubuntu1.1USN-4356-1
squid3Ubuntu
Fixed in:3.5.12-1ubuntu7.11USN-4356-1
Fixed in:3.5.27-1ubuntu1.6USN-4356-1

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityHigh
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityNone
IntegrityNone
AvailabilityHigh

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploit Intelligence

5.76%probability of exploitation in 30 days
92ndpercentile

High risk: more likely to be exploited than 92% of all known CVEs.

References

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.