CVE-2023-46724 SQUID-2023:4 Denial of Service in SSL Certificate validation
Remote attackers can cause a denial of service in Squid proxy via crafted SSL certificates during TLS handshakes when SSL-Bump or HTTPS is enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-46724?
CVE-2023-46724 is a high-severity denial of service vulnerability in Squid-Cache Squid, published on 1 Nov 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Squid is a caching proxy for the Web. Due to an Improper Validation of Specified Index bug, Squid versions 3.3.0.1 through 5.9 and 6.0 prior to 6.4 compiled using `--with-openssl` are vulnerable to a Denial of Service attack against SSL Certificate validation. This problem allows a remote server to perform Denial of Service against Squid Proxy by initiating a TLS Handshake with a specially crafted SSL Certificate in a server certificate chain. This attack is limited to HTTPS and SSL-Bump. This bug is fixed in Squid version 6.4. In addition, patches addressing this problem for the stable releases can be found in Squid's patch archives. Those who you use a prepackaged version of Squid should refer to the package vendor for availability information on updated packages.
Weakness: CWE-786, CWE-823, CWE-129, CWE-1285, CWE-295, CWE-125
Which versions are affected by CVE-2023-46724?
It affects 1 product.
Products include Squid-Cache Squid.
How do I fix CVE-2023-46724?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2023-46724 being exploited?
There is no known exploitation of CVE-2023-46724 in the wild and no public exploit code.
Other vulnerabilities in Squid-Cache Squid
- CVE-2025-62168 Squid vulnerable to information disclosure via authentication credential leakage in error handling
- CVE-2025-54574 Squid's URN Handling can lead to Buffer Overflow
- CVE-2026-33526 Squid vulnerable to Denial of Service in ICP Request handling
- CVE-2026-32748 Squid has Denial of Service in ICP Response handling
- CVE-2023-50269 SQUID-2023:10 Denial of Service in HTTP Request parsing
Sources
Also known as ALPINE-CVE-2023-46724, AZL-31838, CLSA-2023-1700592773, CLSA-2023-1700592975, CLSA-2023-1701285122, CLSA-2023-1701286147 and 5 more.