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VulnerabilityPublished Updated

CVE-2023-46847: squid · Classic Buffer Overflow

Affects squidSource CVE Database V5

0

Not known to be exploited · 78% EPSS · CVSS 8.6 High.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score
8.6High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
78.5% chance of exploitation in 30 days – higher than 99% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 3 Nov 2023

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
Red Hatredhat/squidpkg:rpm/redhat/squidOther threatsAffected
  • =3.2.0.1
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

  1. Immediately identify all Squid proxy instances running version 3.2.0.1 or other vulnerable versions within the network, especially those configured with HTTP Digest Authentication enabled.
  2. Apply vendor-provided patches or upgrade to the latest supported Squid version where this vulnerability is fixed.
  3. If patching is not immediately possible, disable HTTP Digest Authentication on Squid proxies to eliminate the attack vector.
  4. Implement network-level protections such as firewall rules to restrict access to Squid proxy ports from untrusted networks.
  5. Monitor proxy logs and network traffic for unusual patterns indicative of buffer overflow attempts or anomalous large HTTP Digest Authentication payloads.
  6. Conduct regular vulnerability scans and penetration tests focusing on proxy services to detect potential exploitation attempts.
  7. Develop incident response plans specifically addressing proxy service outages and potential DoS scenarios.
  8. Educate IT and security teams about this vulnerability and ensure timely communication of updates from Squid maintainers or Linux distributors.
  9. Consider deploying application-layer firewalls or intrusion prevention systems capable of detecting malformed HTTP Digest Authentication requests.
  10. Maintain an inventory of legacy systems and plan migration away from unsupported Squid versions to reduce future risk.

Description

Squid is vulnerable to a Denial of Service, where a remote attacker can perform buffer overflow attack by writing up to 2 MB of arbitrary data to heap memory when Squid is configured to accept HTTP Digest Authentication.

References

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