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Red Hat: CVE-2019-12521: CVE-2019-12521 squid: Off-by-one error in addStackElement allows for heap buffer overflow and crash (Multiple Advisories)

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Red Hat: CVE-2019-12521: CVE-2019-12521 squid: Off-by-one error in addStackElement allows for heap buffer overflow and crash (Multiple Advisories)

Severity
4
CVSS
(AV:N/AC:M/Au:N/C:N/I:N/A:P)
Published
04/15/2020
Created
11/06/2020
Added
11/05/2020
Modified
12/15/2023

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.

Solution(s)

  • redhat-upgrade-libecap
  • redhat-upgrade-libecap-debuginfo
  • redhat-upgrade-libecap-debugsource
  • redhat-upgrade-libecap-devel
  • redhat-upgrade-squid
  • redhat-upgrade-squid-debuginfo
  • redhat-upgrade-squid-debugsource

References

  • DSA-4682
  • CVE-2019-12521
  • RHSA-2020:4743

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