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Fencer Vulns
medium 6.5

CVE-2021-46784 json

In Squid 3.x through 3.5.28, 4.x through 4.17, and 5.x before 5.6, due to improper buffer management, a Denial of Service can occur when pr…

published 2022-07-17 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-33440

cvss
6.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
5.1%
EPSS 5.1% chance of exploitation in 30 days, percentile 92%
public exploits
0
none known

Summary

In Squid 3.x through 3.5.28, 4.x through 4.17, and 5.x before 5.6, due to improper buffer management, a Denial of Service can occur when processing long Gopher server responses.

Patch / fix

  • squid-cache squid 5.6
  • squid Debian 14, Debian 13, Debian 12 5.6-1

debian advisories DEBIAN-CVE-2021-46784

  • squid Ubuntu 20.04 LTS 4.10-1ubuntu1.6
  • squid Ubuntu 22.04 LTS 5.2-1ubuntu4.1
  • squid3 Ubuntu 18.04 LTS 3.5.27-1ubuntu1.13

ubuntu advisories UBUNTU-CVE-2021-46784

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

  • squid RHEL 7 7:3.5.20-17.el7_9.7
  • squid-sysvinit RHEL 7 7:3.5.20-17.el7_9.7
  • squid-migration-script RHEL 7 7:3.5.20-17.el7_9.7
  • libecap RHEL 8, RHEL 8.4 EUS, RHEL 8.2 EUS +1 more 1.0.1-2.module+el8.1.0+4044+36416a77
  • squid RHEL 9 7:5.2-1.el9_0.1
  • squid RHEL 8 7:4.15-3.module+el8.6.0+15801+8fa20c64.1
  • squid RHEL 8.4 EUS 7:4.11-4.module+el8.4.0+15802+77c2cdda.3
  • squid RHEL 8.2 EUS 7:4.4-8.module+el8.2.0+15803+1b4cda03.4

red hat advisories RHSA-2022:5542RHSA-2022:5528RHSA-2022:5527RHSA-2022:5529RHSA-2022:5530RHSA-2022:5526

  • squid SLES for SAP 15 SP2, SLES for SAP 15 SP1, SLES for SAP 15 +18 more 4.17-150000.5.32.1
  • squid SLES for SAP 12 SP4, SLES 12 SP4-LTSS, SLES 12 SP3-BCL +3 more 3.5.21-26.35.1
  • squid SLES for SAP 12 SP5, SLES 12 SP5 4.17-4.24.1
  • squid SLE Module for Server Applications 15 SP4, openSUSE Leap 15.4 5.6-150400.3.3.1

suse advisories SUSE-SU-2022:2553-1SUSE-SU-2022:2392-1SUSE-SU-2022:2367-1SUSE-SU-2022:2359-1

  • squid openSUSE Tumbleweed 5.6-1.1

opensuse advisories openSUSE-SU-2024:12157-1

  • squid AlmaLinux 8 7:4.15-3.module_el8.6.0+3010+383bc947.1
  • libecap AlmaLinux 8 1.0.1-2.module_el8.6.0+2741+01592ae8
  • squid AlmaLinux 9 7:5.2-1.el9_0.1

almalinux advisories ALSA-2022:5526ALSA-2022:5527

  • squid Rocky Linux 8 7:4.15-3.module+el8.6.0+1044+67ab5d0a.2
  • libecap Rocky Linux 8 1.0.1-2.module+el8.4.0+404+316a0dc5

rocky linux advisories RLSA-2022:5526

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-2021-46784 updated cvss 7.5

squid: DoS when processing gopher server responses

  • Red Hat Enterprise Linux 6 squid, squid34
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AppStream (v. 8) libecap 1.0.1-2.module+el8.1.0+4044+36416a77, squid 4.15-3.module+el8.6.0+15801+8fa20c64.1
    fixed: vendor fix RHSA-2022:5526
  • Red Hat Enterprise Linux AppStream (v. 9) squid 5.2-1.el9_0.1
    fixed: vendor fix RHSA-2022:5527
  • Red Hat Enterprise Linux AppStream E4S (v. 8.1) squid 4.4-8.module+el8.1.0+15805+9a5539dc.4, libecap 1.0.1-2.module+el8.1.0+4044+36416a77
    fixed: vendor fix RHSA-2022:5530
  • Red Hat Enterprise Linux AppStream EUS (v. 8.2) squid 4.4-8.module+el8.2.0+15803+1b4cda03.4, libecap 1.0.1-2.module+el8.1.0+4044+36416a77
    fixed: vendor fix RHSA-2022:5529
  • Red Hat Enterprise Linux AppStream EUS (v.8.4) libecap 1.0.1-2.module+el8.1.0+4044+36416a77, squid 4.11-4.module+el8.4.0+15802+77c2cdda.3
    fixed: vendor fix RHSA-2022:5528
  • Red Hat Enterprise Linux Server (v. 7) squid 3.5.20-17.el7_9.7, squid-sysvinit 3.5.20-17.el7_9.7, squid-migration-script 3.5.20-17.el7_9.7 Red Hat Enterprise Linux Server Optional (v. 7) squid 3.5.20-17.el7_9.7, squid-sysvinit 3.5.20-17.el7_9.7, squid-migration-script 3.5.20-17.el7_9.7 Red Hat Enterprise Linux Workstation (v. 7) squid 3.5.20-17.el7_9.7, squid-sysvinit 3.5.20-17.el7_9.7, squid-migration-script 3.5.20-17.el7_9.7 Red Hat Enterprise Linux Workstation Optional (v. 7) squid 3.5.20-17.el7_9.7, squid-sysvinit 3.5.20-17.el7_9.7, squid-migration-script 3.5.20-17.el7_9.7
    fixed: vendor fix RHSA-2022:5542

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

5.13% chance of exploitation in the next 30 days, higher than 92% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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.