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Fencer Vulns
high 7.5

CVE-2020-8517 json

An issue was discovered in Squid before 4.10.

published 2020-02-04 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-29383

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
6.8%
EPSS 6.8% chance of exploitation in 30 days, percentile 94%
public exploits
0
none known

Summary

An issue was discovered in Squid before 4.10. Due to incorrect input validation, the NTLM authentication credentials parser in ext_lm_group_acl may write to memory outside the credentials buffer. On systems with memory access protections, this can result in the helper process being terminated unexpectedly. This leads to the Squid process also terminating and a denial of service for all clients using the proxy.

Patch / fix

  • squid-cache squid 4.10
  • squid Debian 14, Debian 13, Debian 12 4.10-1

debian advisories DEBIAN-CVE-2020-8517

  • squid Ubuntu 20.04 LTS 4.9-2ubuntu4
  • squid3 Ubuntu 16.04 LTS 3.5.12-1ubuntu7.10
  • squid3 Ubuntu 18.04 LTS 3.5.27-1ubuntu1.5

ubuntu advisories UBUNTU-CVE-2020-8517

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • squid3 SLES 11 SP4-LTSS, SLE Point of Sale 11 SP3 3.1.23-8.16.37.12.1
  • squid SLES for SAP 15, SLES 15-LTSS, SLE Module for Server Applications 15 SP1 +2 more 4.11-5.17.2
  • squid SLES for SAP 12 SP5, SLES 12 SP5 4.11-4.9.1
  • squid SLES for SAP 12 SP4, SLES for SAP 12 SP3, SLES for SAP 12 SP2 +10 more 3.5.21-26.20.1
  • squid SLE Module for Server Applications 15 SP1 4.10-5.14.1
  • squid SLES for SAP 12 SP5, SLES 12 SP5 4.10-4.6.1

suse advisories SUSE-SU-2020:14460-1SUSE-SU-2020:1156-1SUSE-SU-2020:1134-1SUSE-SU-2020:0661-1SUSE-SU-2020:0493-1SUSE-SU-2020:0487-1

  • squid openSUSE Tumbleweed 4.16-1.5
  • squid openSUSE Leap 15.1 4.11-lp151.2.15.2
  • squid openSUSE Leap 15.1 4.10-lp151.2.14.1
  • squid openSUSE Leap 15.1 4.10-lp151.2.11.1

opensuse advisories openSUSE-SU-2024:11403-1openSUSE-SU-2020:0623-1openSUSE-SU-2020:0606-1openSUSE-SU-2020:0307-1

  • squid Alpine 3.24, Alpine 3.23, Alpine 3.22 +13 more 4.10-r0
  • squid Alpine 3.8 3.5.27-r4

alpine advisories ALPINE-CVE-2020-8517

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-8517 updated cvss 8.1

squid: Buffer Overflow in ext_lm_group_acl helper

  • Red Hat Enterprise Linux 5 squid Red Hat Enterprise Linux 6 squid, squid34 Red Hat Enterprise Linux 7 squid, squid-sysvinit, squid-migration-script Red Hat Enterprise Linux 8 squid, libecap
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

6.85% chance of exploitation in the next 30 days, higher than 94% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.