Cyber Resilience

CVE-2023-49286

Squid-Cache Squid ≤ 6.4

Published
04 December 2023
Modified
21 November 2024
Patch / advisory
CVSS Score v3.1 8.6
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
EPSS Score 0.10 95th percentile
Risk Priority 71 floored blend · peak EPSS

Summary

CVE-2023-49286 is a high-severity Incorrect Check of Function Return Value (CWE-253) vulnerability in Squid-Cache Squid. Its CVSS base score is 8.6 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked in the top 5% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

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…

more

is fixed by Squid version 6.5. Users are advised to upgrade. There are no known workarounds for this vulnerability.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
T1489 Service Stop Impact
Adversaries may stop or disable services on a system to render those services unavailable to legitimate users.
T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-46728Same product: Squid-Cache Squid
CVE-2023-50269Same product: Squid-Cache Squid
CVE-2026-50012Same product: Squid-Cache Squid
CVE-2025-62168Same product: Squid-Cache Squid
CVE-2023-49285Same product: Squid-Cache Squid
CVE-2026-33515Same product: Squid-Cache Squid
CVE-2026-32748Same product: Squid-Cache Squid
CVE-2025-59362Same product: Squid-Cache Squid
CVE-2026-33526Same product: Squid-Cache Squid
CVE-2024-37894Same product: Squid-Cache Squid

Affected Assets

squid-cache
squid
≤ 6.4

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 7 hardening rules · 2 OS baselines
Validate
Prove the fix (OWASP ASVS)

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-754

Requires detection and response to audit logging failures as an unusual or exceptional condition.

addresses: CWE-754

Implements detection of unusual or exceptional conditions followed by safe mode entry, reducing the window for exploitation of unchecked conditions.

addresses: CWE-754

Training ensures users perform required checks for unusual or exceptional conditions as part of contingency roles, limiting attacker leverage from skipped validations.

addresses: CWE-754

IR testing directly validates checks for unusual or exceptional conditions that could indicate security incidents.

addresses: CWE-754

Requires ongoing monitoring of organization-defined metrics and analysis, enabling checks for unusual or exceptional conditions.

addresses: CWE-754

Security testing routinely checks for unusual or exceptional inputs/conditions, identifying missing validation steps that flaw remediation then resolves.

addresses: CWE-754

Requires detection of unusual conditions followed by a controlled transition to the defined failure state.

addresses: CWE-754

MTTF determination forces explicit checks for conditions that precede predictable component failure.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly enforce proper error-handling and return-value checking during development.

DE.CM-09 partial match
prevents

Runtime monitoring of software can detect assertion-triggered crashes as adverse events.

ID.RA-01 partial match
prevents

Vulnerability identification processes can discover and record reachable-assertion flaws before deployment.

PR.PS-04 partial match
prevents

Generating logs of exceptions and errors enables detection of improper handling of unusual conditions.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing in development catches missing or incorrect return-value checks.

A.8.15 Logging partial match
finds

Logging can record unhandled exceptions but does not prevent the weakness itself.

finds

Monitoring may detect symptoms of unhandled conditions but does not eliminate the root weakness.

prevents

Secure SDLC mandates return-value checks and error handling, directly reducing CWE-253.

prevents

Application security requirements include robust error handling that mitigates incorrect return-value checks.

prevents

Secure architecture principles require defensive coding practices such as validating function results.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (2 rules)
  • V-248574 YUM must be configured to prevent the installation of patches, service packs, device drivers, or OL 8 system components that have not been digitally signed using a certificate that is recognized and approved by the organization. prevents CWE-754
  • V-248575 OL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-754
Oracle Linux 9 (1 rule)
  • V-271452 OL 9 must use a Linux Security Module configured to enforce limits on system services. prevents CWE-754

References