CVE-2023-46847: squid · Classic Buffer Overflow
Affects squidSource CVE Database V5
Not known to be exploited · 78% EPSS · CVSS 8.6 High.
Data as of 26 Oct 2026, 10:12 UTC
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 3 Nov 2023
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
Red Hatredhat/squidpkg:rpm/redhat/squidOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
- 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.
- Apply vendor-provided patches or upgrade to the latest supported Squid version where this vulnerability is fixed.
- If patching is not immediately possible, disable HTTP Digest Authentication on Squid proxies to eliminate the attack vector.
- Implement network-level protections such as firewall rules to restrict access to Squid proxy ports from untrusted networks.
- Monitor proxy logs and network traffic for unusual patterns indicative of buffer overflow attempts or anomalous large HTTP Digest Authentication payloads.
- Conduct regular vulnerability scans and penetration tests focusing on proxy services to detect potential exploitation attempts.
- Develop incident response plans specifically addressing proxy service outages and potential DoS scenarios.
- Educate IT and security teams about this vulnerability and ensure timely communication of updates from Squid maintainers or Linux distributors.
- Consider deploying application-layer firewalls or intrusion prevention systems capable of detecting malformed HTTP Digest Authentication requests.
- 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
- access.redhat.com/errata/RHSA-2023:6266 (opens in a new tab)
- access.redhat.com/errata/RHSA-2023:6267 (opens in a new tab)
- access.redhat.com/errata/RHSA-2023:6268 (opens in a new tab)
- access.redhat.com/errata/RHSA-2023:6748 (opens in a new tab)
- access.redhat.com/errata/RHSA-2023:6801 (opens in a new tab)
- access.redhat.com/errata/RHSA-2023:6803 (opens in a new tab)
- access.redhat.com/errata/RHSA-2023:6804 (opens in a new tab)
- access.redhat.com/errata/RHSA-2023:6805 (opens in a new tab)
- access.redhat.com/errata/RHSA-2023:6810 (opens in a new tab)
- access.redhat.com/errata/RHSA-2023:6882 (opens in a new tab)
- access.redhat.com/errata/RHSA-2023:6884 (opens in a new tab)
- access.redhat.com/errata/RHSA-2023:7213 (opens in a new tab)
- access.redhat.com/errata/RHSA-2023:7576 (opens in a new tab)
- access.redhat.com/errata/RHSA-2023:7578 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2023-46847 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2245916 (opens in a new tab)
- github.com/squid-cache/squid/security/advisories/GHSA-phqj-m8gv-cq4g (opens in a new tab)
- lists.debian.org/debian-lts-announce/2024/01/msg00003.html (opens in a new tab)
- security.netapp.com/advisory/ntap-20231130-0002/ (opens in a new tab)