CVE-2001-1556

The log files in Apache web server contain information directly supplied by clients and does not filter or quote control characters, which could allow remote attackers to hide HTTP requests and spoof source IP addresses when logs are viewed with UNIX programs such as cat, tail, and grep.

Published: 2001-12-31 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2001-1556 is rated Moderate Risk (52.7/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 3.56%). EPSS rose +2.00% over the last day, indicating growing attacker interest. 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-2001-1556

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 1.56% 3.56% +2.00%
2 2026-06-08 1.77% 1.56% -0.21%
3 2025-12-28 — 1.77% —

Full EPSS history (17 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2001-1556

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2001-1556

OS Trackers for CVE-2001-1556

vendor priority summary link
redhat low — https://access.redhat.com/security/cve/CVE-2001-1556

Vendor comments (NVD) for CVE-2001-1556

  • Red Hat (2006-08-30T00:00:00)

    This is a duplicate CVE name and is a combination of CVE-2003-0020 and CVE-2003-0083.

Affected software / configurations for CVE-2001-1556

Vendor Product Version Raw CPE
apache http_server >= 1.3.0, < 1.3.31 cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*
apache http_server >= 2.0.0, < 2.0.49 cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*

References for CVE-2001-1556

cvelogic Threat Intelligence