SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2011-5279

CRLF injection vulnerability in the CGI implementation in Microsoft Internet Information Services (IIS) 4.x and 5.x on Windows NT and Windows 2000 allows remote attackers to modify arbitrary uppercase environment variables via a \n (newline) character…

MEDIUM 5.0EPSS 19.6%

Does this matter?

EPSS puts the probability of exploitation in the next 30 days at 19.6%, higher than 97% of all known CVEs. Patch or mitigate before the next change window.

Description

CRLF injection vulnerability in the CGI implementation in Microsoft Internet Information Services (IIS) 4.x and 5.x on Windows NT and Windows 2000 allows remote attackers to modify arbitrary uppercase environment variables via a \n (newline) character in an HTTP header.

CVSS 2.0
5.0 MEDIUMAV:N/AC:L/Au:N/C:N/I:P/A:N
EPSS
19.59% probability · 97th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Affected
microsoft/internet information services
Source
cve@mitre.org
EPSS trend
0%10%20%26 October 2026: 19.59%26 October 202626 October 2026

EPSS 19.6% since 26 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.