CVE-2023-49286 | Denial of Service in Helper Process management

Squid is a caching proxy for the Web supporting HTTP, HTTPS, FTP, and more. Due to an Incorrect Check of Function Return Value bug Squid is vulnerable to a Denial of Service attack against its Helper process management. This bug is fixed by Squid version 6.5. Users are advised to upgrade. There are no known workarounds for this vulnerability.

Published: 2023-12-04 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-49286 is rated Moderate Risk (62.8/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.73%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2023-49286

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 2026-04-19 2.24% 1.73% -0.51%
2 2026-04-17 1.88% 2.24% +0.36%
3 2026-01-13 — 1.88% —

Full EPSS history (40 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-49286

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.6 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 4.0 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]

Weakness enumeration for CVE-2023-49286

OS Trackers for CVE-2023-49286

vendor priority summary link
alpine — CVE-2023-49286: 1 source package rows (squid); 67 state rows across 7 repos (3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 5, open 62. https://security.alpinelinux.org/vuln/CVE-2023-49286
debian low CVE-2023-49286 low 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-2023-49286
redhat high — https://access.redhat.com/security/cve/CVE-2023-49286
suse high — https://www.suse.com/security/cve/CVE-2023-49286/
ubuntu medium CVE-2023-49286 medium priority: Ubuntu including 2 source packages (squid, squid3), 18 status rows across 9 suites (bionic, focal, jammy, lunar, mantic, noble, trusty, upstream, xenial): released 8, DNE 5, ignored 4, needs-triage 1. https://ubuntu.com/security/CVE-2023-49286

Affected software / configurations for CVE-2023-49286

Vendor Product Version Raw CPE
squid-cache squid <= 6.4 cpe:2.3:a:squid-cache:squid:*:*:*:*:*:*:*:*

References for CVE-2023-49286

cvelogic Threat Intelligence