CVE-2021-31806

Exploitation

Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.

SSVC decision

Not assessed by CISA

EPSS probability

95.78% probability of exploitation activity in the next 30 days.

EPSS percentile

Ranks above 99.9% of scored records. A rank, not a probability.

NVD base score

6.5 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

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

NVD analysis status

Modified. NVD last modified this record on 2026-06-17.

Red Hat severity

Moderate. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2021-05-27 00:00Z5 YR AGO

Last updated

2024-08-03 23:10Z2 YR AGO

Reserved

2021-04-26

Assigning CNA

mitre

Record state

PUBLISHED

Severity

Not rated by the issuing CNA

CNA CVSS vector

Not published by the issuing CNA

Weaknesses

• CWE-116Improper Encoding or Escaping of OutputClass
• CWE-20Improper Input ValidationClass

Data version

5.1

Document digest

f8e4e304a3614187827e036ba241990dafcf02d77e4d83c22e64811ba370f898

• github.comhttps://github.com/squid-cache/squid/security/advisories/GHSA-pxwq-f3qr-w2xf
• www.squid-cache.orghttp://www.squid-cache.org/Versions/v4/changesets/squid-4-e7cf864f938f24eea8af0692c04d16790983c823.patch
• www.debian.orgDSA-4924https://www.debian.org/security/2021/dsa-4924vendor-advisory
• lists.fedoraproject.orgFEDORA-2021-c0bec55ec7https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LSQ3U54ZCNXR44QRPW3AV2VCS6K3TKCF/vendor-advisory
• lists.fedoraproject.orgFEDORA-2021-24af72ff2chttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/T4EPIWUZDJAXADDHVOPKRBTQHPBR6H66/vendor-advisory
• lists.debian.org[debian-lts-announce] 20210614 [SECURITY] [DLA 2685-1] squid3 security updatehttps://lists.debian.org/debian-lts-announce/2021/06/msg00014.htmlmailing-list
• security.netapp.comhttps://security.netapp.com/advisory/ntap-20210716-0007/
• www.openwall.com[oss-security] 20231011 Squid Caching Proxy Security Audit: 55 Vulnerabilities, 35 0days.http://www.openwall.com/lists/oss-security/2023/10/11/3mailing-list
• seclists.org20231016 Squid Caching Proxy Security Audit: 55 Vulnerabilities, 35 0days.http://seclists.org/fulldisclosure/2023/Oct/14mailing-list