CVE-2021-28662
If a remote server sends a certain response header over HTTP or HTTPS, there is a denial of service.
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 71.8%, higher than 99% of all known CVEs. Patch or mitigate before the next change window.
Description
An issue was discovered in Squid 4.x before 4.15 and 5.x before 5.0.6. If a remote server sends a certain response header over HTTP or HTTPS, there is a denial of service. This header can plausibly occur in benign network traffic.
- CVSS 3.1
- 6.5 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
- EPSS
- 71.76% probability · 99th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-116
- Affected
- squid-cache/squid · debian/debian linux · fedoraproject/fedora
- Source
- cve@mitre.org
EPSS 71.8% since 26 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://seclists.org/fulldisclosure/2023/Oct/14Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2023/10/11/3Mailing List, Third Party Advisory
- http://www.squid-cache.org/Versions/v6/changesets/squid-6-051824924c709bd6162a378f746fb859454c674e.patchPatch, Vendor Advisory
- https://github.com/squid-cache/squid/commit/051824924c709bd6162a378f746fb859454c674ePatch, Third Party Advisory
- https://github.com/squid-cache/squid/security/advisories/GHSA-jjq6-mh2h-g39hPatch, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LSQ3U54ZCNXR44QRPW3AV2VCS6K3TKCF/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/T4EPIWUZDJAXADDHVOPKRBTQHPBR6H66/
- https://www.debian.org/security/2021/dsa-4924Third Party Advisory
- http://seclists.org/fulldisclosure/2023/Oct/14Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2023/10/11/3Mailing List, Third Party Advisory
- http://www.squid-cache.org/Versions/v6/changesets/squid-6-051824924c709bd6162a378f746fb859454c674e.patchPatch, Vendor Advisory
- https://github.com/squid-cache/squid/commit/051824924c709bd6162a378f746fb859454c674ePatch, Third Party Advisory
- https://github.com/squid-cache/squid/security/advisories/GHSA-jjq6-mh2h-g39hPatch, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LSQ3U54ZCNXR44QRPW3AV2VCS6K3TKCF/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/T4EPIWUZDJAXADDHVOPKRBTQHPBR6H66/
- https://www.debian.org/security/2021/dsa-4924Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.