The htcpHandleTstRequest function in htcp.c in Squid 2.x before 2.6.STABLE24 and 2.7 before 2.7.STABLE8, and htcp.cc in 3.0 before 3.0.STABLE24, allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via crafted packets to the HTCP port.
Conclusion & alert: CVE-2010-0639 is rated Moderate Risk (49.3/100): CVSS Medium severity, with high exploitation likelihood (EPSS 30.34%, 98th percentile). Core evidence: EPSS ranks this CVE among the most likely to be exploited in the near term. Mandatory action: High exploitation likelihood—assess exposure and prioritize remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-15 | 49.37% | 30.34% | -19.03% |
| 2 | 2025-07-30 | 56.16% | 49.37% | -6.79% |
| 3 | 2025-03-30 | — | 56.16% | — |
Full EPSS history (10 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 5.0 | 2.0 | MEDIUM |
|
10.0 | 2.9 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
not yet assigned | CVE-2010-0639 not yet assigned priority: Debian including 1 source packages (squid), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. | https://security-tracker.debian.org/tracker/CVE-2010-0639 |
gentoo
|
high | CVE-2010-0639: 1 GLSA(s) (201110-24), 1 atom(s) (net-proxy/squid); latest impact high. | https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2010-0639 |
redhat
|
low | — | https://access.redhat.com/security/cve/CVE-2010-0639 |
ubuntu
|
medium | CVE-2010-0639 medium priority: Ubuntu including 2 source packages (squid, squid3), 20 status rows across 10 suites (dapper, hardy, intrepid, jaunty, karmic, lucid, maverick, natty, oneiric, upstream): released 10, ignored 4, not-affected 4, DNE 1, needs-triage 1. | https://ubuntu.com/security/CVE-2010-0639 |
: Per: http://cwe.mitre.org/data/definitions/476.html 'NULL Pointer Dereference'
Not vulnerable. This issue did not affect the versions of squid as shipped with Red Hat Enterprise Linux 3, 4, or 5. Those versions are not compiled with the support for HTCP protocol.
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| squid-cache | squid | 2.0 | cpe:2.3:a:squid-cache:squid:2.0:*:*:*:*:*:*:* |
| squid-cache | squid | 2.1 | cpe:2.3:a:squid-cache:squid:2.1:*:*:*:*:*:*:* |
| squid-cache | squid | 2.2 | cpe:2.3:a:squid-cache:squid:2.2:*:*:*:*:*:*:* |
| squid-cache | squid | 2.3 | cpe:2.3:a:squid-cache:squid:2.3:*:*:*:*:*:*:* |
| squid-cache | squid | 2.4 | cpe:2.3:a:squid-cache:squid:2.4:*:*:*:*:*:*:* |
| squid-cache | squid | 2.5 | cpe:2.3:a:squid-cache:squid:2.5:*:*:*:*:*:*:* |
| squid-cache | squid | 2.6 | cpe:2.3:a:squid-cache:squid:2.6:*:*:*:*:*:*:* |
| squid-cache | squid | 2.7 | cpe:2.3:a:squid-cache:squid:2.7:*:*:*:*:*:*:* |
| squid-cache | squid | 2.7 | cpe:2.3:a:squid-cache:squid:2.7:stable3:*:*:*:*:*:* |
| squid-cache | squid | 2.7 | cpe:2.3:a:squid-cache:squid:2.7:stable4:*:*:*:*:*:* |
| squid-cache | squid | 3.0 | cpe:2.3:a:squid-cache:squid:3.0:*:*:*:*:*:*:* |
| squid-cache | squid | 3.0.stable1 | cpe:2.3:a:squid-cache:squid:3.0.stable1:*:*:*:*:*:*:* |
| squid-cache | squid | 3.0.stable2 | cpe:2.3:a:squid-cache:squid:3.0.stable2:*:*:*:*:*:*:* |
| squid-cache | squid | 3.0.stable3 | cpe:2.3:a:squid-cache:squid:3.0.stable3:*:*:*:*:*:*:* |
| squid-cache | squid | 3.0.stable4 | cpe:2.3:a:squid-cache:squid:3.0.stable4:*:*:*:*:*:*:* |
| squid-cache | squid | 3.0.stable5 | cpe:2.3:a:squid-cache:squid:3.0.stable5:*:*:*:*:*:*:* |
| squid-cache | squid | 3.0.stable6 | cpe:2.3:a:squid-cache:squid:3.0.stable6:*:*:*:*:*:*:* |
| squid-cache | squid | 3.0.stable7 | cpe:2.3:a:squid-cache:squid:3.0.stable7:*:*:*:*:*:*:* |
| squid-cache | squid | 3.0.stable8 | cpe:2.3:a:squid-cache:squid:3.0.stable8:*:*:*:*:*:*:* |
| squid-cache | squid | 3.0.stable9 | cpe:2.3:a:squid-cache:squid:3.0.stable9:*:*:*:*:*:*:* |
| squid-cache | squid | 3.0.stable11 | cpe:2.3:a:squid-cache:squid:3.0.stable11:*:*:*:*:*:*:* |
| squid-cache | squid | 3.0.stable12 | cpe:2.3:a:squid-cache:squid:3.0.stable12:*:*:*:*:*:*:* |
| squid-cache | squid | 3.0.stable13 | cpe:2.3:a:squid-cache:squid:3.0.stable13:*:*:*:*:*:*:* |
| squid-cache | squid | 3.0.stable14 | cpe:2.3:a:squid-cache:squid:3.0.stable14:*:*:*:*:*:*:* |
| squid-cache | squid | 3.0.stable15 | cpe:2.3:a:squid-cache:squid:3.0.stable15:*:*:*:*:*:*:* |
| squid-cache | squid | 3.0.stable16 | cpe:2.3:a:squid-cache:squid:3.0.stable16:*:*:*:*:*:*:* |
| squid-cache | squid | 3.0.stable17 | cpe:2.3:a:squid-cache:squid:3.0.stable17:*:*:*:*:*:*:* |
| squid-cache | squid | 3.0.stable18 | cpe:2.3:a:squid-cache:squid:3.0.stable18:*:*:*:*:*:*:* |
| squid-cache | squid | 3.0.stable19 | cpe:2.3:a:squid-cache:squid:3.0.stable19:*:*:*:*:*:*:* |
| squid-cache | squid | 3.0.stable20 | cpe:2.3:a:squid-cache:squid:3.0.stable20:*:*:*:*:*:*:* |
| squid-cache | squid | 3.0.stable21 | cpe:2.3:a:squid-cache:squid:3.0.stable21:*:*:*:*:*:*:* |
| squid-cache | squid | 3.0.stable22 | cpe:2.3:a:squid-cache:squid:3.0.stable22:*:*:*:*:*:*:* |
| squid-cache | squid | 3.0.stable23 | cpe:2.3:a:squid-cache:squid:3.0.stable23:*:*:*:*:*:*:* |